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expat: backport CVE-2026-45186 fix (attribute collision check DoS)

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Backport CVE-2026-45186 fix from upstream PR #1216 to
expat-2.7.3. The patch includes 7 cherry-picked commits:
4 test infrastructure updates and 3 library changes that
introduce a hash table for attribute name deduplication in
ELEMENT_TYPE. Added expat-2.7.3-CVE-2026-45186.patch and
changed %autosetup to use -p2 to correctly strip the
a/expat/ path prefix.

CVE: CVE-2026-45186
Upstream patches:
 - https://github.com/libexpat/libexpat/pull/1216.patch
Resolves: RHEL-177983

This commit was backported by Ymir, a Red Hat Enterprise Linux software maintenance AI agent.

Assisted-by: Ymir
This commit is contained in:
RHEL Packaging Agent 2026-07-15 06:42:16 +00:00
parent eef65ac89e
commit 66bbbc6015
2 changed files with 591 additions and 1 deletions
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586
expat-2.7.3-CVE-2026-45186.patch Normal file
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@ -0,0 +1,586 @@
From 5ec3c665d9b29f7c0373873080a88f4f826d2d6c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Berkay=20Eren=20=C3=9Cr=C3=BCn?= <berkay.ueruen@siemens.com>
Date: Fri, 13 Mar 2026 13:26:45 +0100
Subject: [PATCH 1/7] Make "counting_start_element_handler" count default attrs
---
expat/tests/basic_tests.c | 8 ++++----
expat/tests/handlers.c | 2 +-
expat/tests/handlers.h | 1 +
3 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/expat/tests/basic_tests.c b/expat/tests/basic_tests.c
index 0231e094..cc356e95 100644
--- a/expat/tests/basic_tests.c
+++ b/expat/tests/basic_tests.c
@@ -2466,9 +2466,9 @@ START_TEST(test_attributes) {
{XCS("id"), XCS("one")},
{NULL, NULL}};
AttrInfo tag_info[] = {{XCS("c"), XCS("3")}, {NULL, NULL}};
- ElementInfo info[] = {{XCS("doc"), 3, XCS("id"), NULL},
- {XCS("tag"), 1, NULL, NULL},
- {NULL, 0, NULL, NULL}};
+ ElementInfo info[] = {{XCS("doc"), 3, 0, XCS("id"), NULL},
+ {XCS("tag"), 1, 0, NULL, NULL},
+ {NULL, 0, 0, NULL, NULL}};
info[0].attributes = doc_info;
info[1].attributes = tag_info;
@@ -5499,7 +5499,7 @@ START_TEST(test_deep_nested_attribute_entity) {
(long unsigned)(N_LINES - 1));
AttrInfo doc_info[] = {{XCS("name"), XCS("deepText")}, {NULL, NULL}};
- ElementInfo info[] = {{XCS("foo"), 1, NULL, NULL}, {NULL, 0, NULL, NULL}};
+ ElementInfo info[] = {{XCS("foo"), 1, 0, NULL, NULL}, {NULL, 0, 0, NULL, NULL}};
info[0].attributes = doc_info;
XML_Parser parser = XML_ParserCreate(NULL);
diff --git a/expat/tests/handlers.c b/expat/tests/handlers.c
index 5bca2b1f..72b4240f 100644
--- a/expat/tests/handlers.c
+++ b/expat/tests/handlers.c
@@ -136,7 +136,7 @@ counting_start_element_handler(void *userData, const XML_Char *name,
fail("ID does not have the correct name");
return;
}
- for (i = 0; i < info->attr_count; i++) {
+ for (i = 0; i < info->attr_count + info->default_attr_count; i++) {
attr = info->attributes;
while (attr->name != NULL) {
if (! xcstrcmp(atts[0], attr->name))
diff --git a/expat/tests/handlers.h b/expat/tests/handlers.h
index fa6267fb..1970fe66 100644
--- a/expat/tests/handlers.h
+++ b/expat/tests/handlers.h
@@ -88,6 +88,7 @@ typedef struct attrInfo {
typedef struct elementInfo {
const XML_Char *name;
int attr_count;
+ int default_attr_count;
const XML_Char *id_name;
AttrInfo *attributes;
} ElementInfo;
From 5cbc6b297c87021b5659d4520654cf746b2a4850 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Berkay=20Eren=20=C3=9Cr=C3=BCn?= <berkay.ueruen@siemens.com>
Date: Fri, 13 Mar 2026 13:27:31 +0100
Subject: [PATCH 2/7] test(attlist): Cover duplicate attribute names
Co-authored-by: Sebastian Pipping <sebastian@pipping.org>
---
expat/tests/basic_tests.c | 282 ++++++++++++++++++++++++++++++++++++++
1 file changed, 282 insertions(+)
diff --git a/expat/tests/basic_tests.c b/expat/tests/basic_tests.c
index cc356e95..9729757e 100644
--- a/expat/tests/basic_tests.c
+++ b/expat/tests/basic_tests.c
@@ -2489,6 +2489,279 @@ START_TEST(test_attributes) {
}
END_TEST
+START_TEST(test_duplicate_cdata_attribute) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one definition is provided for the same attribute of a given
+ element type, the first declaration is binding and later declarations are
+ ignored.
+ */
+
+ const char *text
+ = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc attribute CDATA 'expected' attribute CDATA 'ignored'>\n"
+ "]>\n"
+ "<doc/>\n";
+ AttrInfo doc_info[] = {{XCS("attribute"), XCS("expected")}, {NULL, NULL}};
+ ElementInfo info[]
+ = {{XCS("doc"), 0, 1, NULL, doc_info}, {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_id_attribute_1) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one definition is provided for the same attribute of a given
+ element type, the first declaration is binding and later declarations are
+ ignored.
+ */
+
+ const char *text
+ = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc identifier CDATA 'expected' identifier ID #REQUIRED>\n"
+ "]>\n"
+ "<doc/>\n";
+ AttrInfo doc_info[] = {{XCS("identifier"), XCS("expected")}, {NULL, NULL}};
+ ElementInfo info[]
+ = {{XCS("doc"), 0, 1, NULL, doc_info}, {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_id_attribute_2) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one definition is provided for the same attribute of a given
+ element type, the first declaration is binding and later declarations are
+ ignored.
+ */
+
+ const char *text
+ = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc identifier ID #REQUIRED identifier CDATA 'unexpected'>\n"
+ "]>\n"
+ "<doc/>\n";
+ AttrInfo doc_info[] = {{NULL, NULL}};
+
+ ElementInfo info[]
+ = {{XCS("doc"), 0, 0, NULL, doc_info}, {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_cdata_attribute_multiple_attlistdecl) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one AttlistDecl is provided for a given element type,
+ the contents of all those provided are merged.
+ */
+ const char *text = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc attribute CDATA 'expected'>\n"
+ " <!ATTLIST doc attribute CDATA 'ignored'>\n"
+ "]>\n"
+ "<doc/>\n";
+ AttrInfo doc_info[] = {{XCS("attribute"), XCS("expected")}, {NULL, NULL}};
+ ElementInfo info[]
+ = {{XCS("doc"), 0, 1, NULL, doc_info}, {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_cdata_attribute_multiple_attlistdecl_2) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one AttlistDecl is provided for a given element type,
+ the contents of all those provided are merged.
+ */
+ const char *text = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc attribute CDATA 'expected_doc'>\n"
+ " <!ATTLIST tag attribute CDATA 'expected_tag'>\n"
+ " <!ATTLIST doc attribute CDATA 'ignored_doc'>\n"
+ "]>\n"
+ "<doc><tag></tag></doc>\n";
+ AttrInfo doc_info[] = {{XCS("attribute"), XCS("expected_doc")}, {NULL, NULL}};
+ AttrInfo tag_info[] = {{XCS("attribute"), XCS("expected_tag")}, {NULL, NULL}};
+ ElementInfo info[] = {{XCS("doc"), 0, 1, NULL, doc_info},
+ {XCS("tag"), 0, 1, NULL, tag_info},
+ {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_cdata_attribute_multiple_attlistdecl_3) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one AttlistDecl is provided for a given element type,
+ the contents of all those provided are merged.
+ */
+ const char *text
+ = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc attribute CDATA 'expected_doc'>\n"
+ " <!ATTLIST tag attribute CDATA 'expected_tag'>\n"
+ " <!ATTLIST doc second_attribute CDATA 'second_expected_doc' attribute CDATA 'ignored_doc'>\n"
+ "]>\n"
+ "<doc><tag></tag></doc>\n";
+ AttrInfo doc_info[] = {{XCS("attribute"), XCS("expected_doc")},
+ {XCS("second_attribute"), XCS("second_expected_doc")},
+ {NULL, NULL}};
+ AttrInfo tag_info[] = {{XCS("attribute"), XCS("expected_tag")}, {NULL, NULL}};
+ ElementInfo info[] = {{XCS("doc"), 0, 2, NULL, doc_info},
+ {XCS("tag"), 0, 1, NULL, tag_info},
+ {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
+START_TEST(test_duplicate_id_attribute_multiple_attlistdecl) {
+ /*
+ https://www.w3.org/TR/xml/#attdecls
+
+ Test the following statement from the linked specification:
+ When more than one AttlistDecl is provided for a given element type,
+ the contents of all those provided are merged.
+ */
+ const char *text = "<!DOCTYPE doc [\n"
+ " <!ATTLIST doc identifier ID #REQUIRED>\n"
+ " <!ATTLIST tag identifier CDATA 'identifier_tag'>\n"
+ " <!ATTLIST doc identifier CDATA 'ignored'>\n"
+ "]>\n"
+ "<doc identifier='doc_identity'><tag></tag></doc>\n";
+ AttrInfo doc_info[]
+ = {{XCS("identifier"), XCS("doc_identity")}, {NULL, NULL}};
+ AttrInfo tag_info[]
+ = {{XCS("identifier"), XCS("identifier_tag")}, {NULL, NULL}};
+ ElementInfo info[] = {{XCS("doc"), 1, 0, XCS("identifier"), doc_info},
+ {XCS("tag"), 0, 1, NULL, tag_info},
+ {NULL, 0, 0, NULL, NULL}};
+
+ XML_Parser parser = XML_ParserCreate(NULL);
+ assert_true(parser != NULL);
+
+ ParserAndElementInfo parserAndElementInfos = {
+ parser,
+ info,
+ };
+
+ XML_SetStartElementHandler(parser, counting_start_element_handler);
+ XML_SetUserData(parser, &parserAndElementInfos);
+
+ if (_XML_Parse_SINGLE_BYTES(parser, text, (int)strlen(text), XML_TRUE)
+ != XML_STATUS_OK)
+ xml_failure(parser);
+
+ XML_ParserFree(parser);
+}
+END_TEST
+
/* Test reset works correctly in the middle of processing an internal
* entity. Exercises some obscure code in XML_ParserReset().
*/
@@ -6311,6 +6584,15 @@ make_basic_test_case(Suite *s) {
tcase_add_test__ifdef_xml_dtd(tc_basic, test_empty_foreign_dtd);
tcase_add_test(tc_basic, test_set_base);
tcase_add_test(tc_basic, test_attributes);
+ tcase_add_test(tc_basic, test_duplicate_cdata_attribute);
+ tcase_add_test(tc_basic, test_duplicate_id_attribute_1);
+ tcase_add_test(tc_basic, test_duplicate_id_attribute_2);
+ tcase_add_test(tc_basic, test_duplicate_cdata_attribute_multiple_attlistdecl);
+ tcase_add_test(tc_basic,
+ test_duplicate_cdata_attribute_multiple_attlistdecl_2);
+ tcase_add_test(tc_basic,
+ test_duplicate_cdata_attribute_multiple_attlistdecl_3);
+ tcase_add_test(tc_basic, test_duplicate_id_attribute_multiple_attlistdecl);
tcase_add_test__if_xml_ge(tc_basic, test_reset_in_entity);
tcase_add_test(tc_basic, test_resume_invalid_parse);
tcase_add_test(tc_basic, test_resume_resuspended);
From 58877476211c8cc6337e7d0617d85d470437126a Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Mon, 20 Apr 2026 13:44:43 +0200
Subject: [PATCH 3/7] tests: Define .attributes the first time around
---
expat/tests/basic_tests.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/expat/tests/basic_tests.c b/expat/tests/basic_tests.c
index 9729757e..cdcae029 100644
--- a/expat/tests/basic_tests.c
+++ b/expat/tests/basic_tests.c
@@ -2466,11 +2466,9 @@ START_TEST(test_attributes) {
{XCS("id"), XCS("one")},
{NULL, NULL}};
AttrInfo tag_info[] = {{XCS("c"), XCS("3")}, {NULL, NULL}};
- ElementInfo info[] = {{XCS("doc"), 3, 0, XCS("id"), NULL},
- {XCS("tag"), 1, 0, NULL, NULL},
+ ElementInfo info[] = {{XCS("doc"), 3, 0, XCS("id"), doc_info},
+ {XCS("tag"), 1, 0, NULL, tag_info},
{NULL, 0, 0, NULL, NULL}};
- info[0].attributes = doc_info;
- info[1].attributes = tag_info;
XML_Parser parser = XML_ParserCreate(NULL);
assert_true(parser != NULL);
@@ -5772,8 +5770,8 @@ START_TEST(test_deep_nested_attribute_entity) {
(long unsigned)(N_LINES - 1));
AttrInfo doc_info[] = {{XCS("name"), XCS("deepText")}, {NULL, NULL}};
- ElementInfo info[] = {{XCS("foo"), 1, 0, NULL, NULL}, {NULL, 0, 0, NULL, NULL}};
- info[0].attributes = doc_info;
+ ElementInfo info[]
+ = {{XCS("foo"), 1, 0, NULL, doc_info}, {NULL, 0, 0, NULL, NULL}};
XML_Parser parser = XML_ParserCreate(NULL);
ParserAndElementInfo parserPlusElemenInfo = {parser, info};
From b3afb59fdcdb11cb994f65a3566bd97de793a2ff Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Mon, 13 Apr 2026 01:34:03 +0200
Subject: [PATCH 4/7] tests: Make counting_start_element_handler enforce
complete attribute lists
---
expat/tests/handlers.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/expat/tests/handlers.c b/expat/tests/handlers.c
index 72b4240f..8008bc21 100644
--- a/expat/tests/handlers.c
+++ b/expat/tests/handlers.c
@@ -154,6 +154,9 @@ counting_start_element_handler(void *userData, const XML_Char *name,
/* Remember, two entries in atts per attribute (see above) */
atts += 2;
}
+
+ // Self-test that the test case's list of expected attributes is complete
+ assert_true(atts[0] == NULL);
}
void XMLCALL
From c54aa8e912db8d0bcccbc3ceebaea011865a5024 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Sun, 8 Mar 2026 22:14:41 +0100
Subject: [PATCH 5/7] lib: Extract a constant for upcoming reuse
---
expat/lib/xmlparse.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index a187a3a1..5cf2c279 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -7685,8 +7685,9 @@ dtdCopy(XML_Parser oldParser, DTD *newDtd, const DTD *oldDtd,
newE->prefix = (PREFIX *)lookup(oldParser, &(newDtd->prefixes),
oldE->prefix->name, 0);
for (i = 0; i < newE->nDefaultAtts; i++) {
+ const XML_Char *const attributeName = oldE->defaultAtts[i].id->name;
newE->defaultAtts[i].id = (ATTRIBUTE_ID *)lookup(
- oldParser, &(newDtd->attributeIds), oldE->defaultAtts[i].id->name, 0);
+ oldParser, &(newDtd->attributeIds), attributeName, 0);
newE->defaultAtts[i].isCdata = oldE->defaultAtts[i].isCdata;
if (oldE->defaultAtts[i].value) {
newE->defaultAtts[i].value
From be28a1e7abf734463b0388a9dc58320892e4d256 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Sun, 8 Mar 2026 23:05:49 +0100
Subject: [PATCH 6/7] lib: Introduce ELEMENT_TYPE.defaultAttsNames
---
expat/lib/xmlparse.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index 5cf2c279..8c0d2a43 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -389,6 +389,7 @@ typedef struct {
int nDefaultAtts;
int allocDefaultAtts;
DEFAULT_ATTRIBUTE *defaultAtts;
+ HASH_TABLE defaultAttsNames;
} ELEMENT_TYPE;
typedef struct {
@@ -3845,6 +3846,8 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
sizeof(ELEMENT_TYPE));
if (! elementType)
return XML_ERROR_NO_MEMORY;
+ if (! elementType->defaultAttsNames.parser)
+ hashTableInit(&(elementType->defaultAttsNames), parser);
if (parser->m_ns && ! setElementTypePrefix(parser, elementType))
return XML_ERROR_NO_MEMORY;
}
@@ -7526,6 +7529,7 @@ dtdReset(DTD *p, XML_Parser parser) {
ELEMENT_TYPE *e = (ELEMENT_TYPE *)hashTableIterNext(&iter);
if (! e)
break;
+ hashTableDestroy(&(e->defaultAttsNames));
if (e->allocDefaultAtts != 0)
FREE(parser, e->defaultAtts);
}
@@ -7567,6 +7571,7 @@ dtdDestroy(DTD *p, XML_Bool isDocEntity, XML_Parser parser) {
ELEMENT_TYPE *e = (ELEMENT_TYPE *)hashTableIterNext(&iter);
if (! e)
break;
+ hashTableDestroy(&(e->defaultAttsNames));
if (e->allocDefaultAtts != 0)
FREE(parser, e->defaultAtts);
}
@@ -7660,6 +7665,10 @@ dtdCopy(XML_Parser oldParser, DTD *newDtd, const DTD *oldDtd,
sizeof(ELEMENT_TYPE));
if (! newE)
return 0;
+
+ if (! newE->defaultAttsNames.parser)
+ hashTableInit(&(newE->defaultAttsNames), parser);
+
if (oldE->nDefaultAtts) {
/* Detect and prevent integer overflow.
* The preprocessor guard addresses the "always false" warning
@@ -7696,6 +7705,12 @@ dtdCopy(XML_Parser oldParser, DTD *newDtd, const DTD *oldDtd,
return 0;
} else
newE->defaultAtts[i].value = NULL;
+
+ NAMED *const nameAddedOrFound = (NAMED *)lookup(
+ parser, &(newE->defaultAttsNames), attributeName, sizeof(NAMED));
+ if (! nameAddedOrFound) {
+ return 0;
+ }
}
}
@@ -8423,6 +8438,8 @@ getElementType(XML_Parser parser, const ENCODING *enc, const char *ptr,
sizeof(ELEMENT_TYPE));
if (! ret)
return NULL;
+ if (! ret->defaultAttsNames.parser)
+ hashTableInit(&(ret->defaultAttsNames), getRootParserOf(parser, NULL));
if (ret->name != name)
poolDiscard(&dtd->pool);
else {
From b8960a10a17a1706ad9c07b31ed10fbf1993a544 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Sun, 8 Mar 2026 23:06:29 +0100
Subject: [PATCH 7/7] lib: Leverage ELEMENT_TYPE.defaultAttsNames for attribute
collision detection
.. to resolve quadratic runtime behavior
---
expat/lib/xmlparse.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index 8c0d2a43..c5835738 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -7162,10 +7162,10 @@ defineAttribute(ELEMENT_TYPE *type, ATTRIBUTE_ID *attId, XML_Bool isCdata,
if (value || isId) {
/* The handling of default attributes gets messed up if we have
a default which duplicates a non-default. */
- int i;
- for (i = 0; i < type->nDefaultAtts; i++)
- if (attId == type->defaultAtts[i].id)
- return 1;
+ NAMED *const nameFound
+ = (NAMED *)lookup(parser, &(type->defaultAttsNames), attId->name, 0);
+ if (nameFound)
+ return 1;
if (isId && ! type->idAtt && ! attId->xmlns)
type->idAtt = attId;
}
@@ -7212,6 +7212,12 @@ defineAttribute(ELEMENT_TYPE *type, ATTRIBUTE_ID *attId, XML_Bool isCdata,
att->isCdata = isCdata;
if (! isCdata)
attId->maybeTokenized = XML_TRUE;
+
+ NAMED *const nameAddedOrFound = (NAMED *)lookup(
+ parser, &(type->defaultAttsNames), attId->name, sizeof(NAMED));
+ if (! nameAddedOrFound)
+ return 0;
+
type->nDefaultAtts += 1;
return 1;
}

6
expat.spec
View File

@ -10,6 +10,10 @@ Source2: https://keys.openpgp.org/vks/v1/by-fingerprint/3176EF7DB2367F1FCA4F306B
URL: https://libexpat.github.io/
VCS: git:https://github.com/libexpat/libexpat.git
License: MIT
# https://issues.redhat.com/browse/RHEL-177983
# https://github.com/libexpat/libexpat/pull/1216
Patch0: expat-2.7.3-CVE-2026-45186.patch
BuildRequires: autoconf, libtool, xmlto, gcc-c++
BuildRequires: make
BuildRequires: gnupg2
@ -40,7 +44,7 @@ Install it if you need to link statically with expat.
%prep
%{gpgverify} --keyring='%{SOURCE2}' --signature='%{SOURCE1}' --data='%{SOURCE0}'
%autosetup
%autosetup -p2
sed -i 's/install-data-hook/do-nothing-please/' lib/Makefile.am
./buildconf.sh