From 21e042597f0569b0229fd2826de3e47319d9fa9c Mon Sep 17 00:00:00 2001 From: RHEL Packaging Agent Date: Thu, 20 Aug 2026 20:58:32 +0000 Subject: [PATCH] Fix CVE-2026-58010: off-by-one in GVariant tuple offset checking Add patch for CVE-2026-58010 which fixes an off-by-one error in the GVariant tuple serialiser's normal form checking code. The bug allowed a single byte out-of-bounds read when verifying padding bytes in a short (non-normal) tuple. The patch changes the offset comparison from `>` to `>=` in gvs_tuple_is_normal() and adds a regression test. An additional fix includes `` in the test file so that the new test using `uint8_t` compiles correctly against the older glib 2.80.4 codebase. CVE: CVE-2026-58010 Upstream patches: - https://gitlab.gnome.org/GNOME/glib/-/commit/8338414f6560216efe67d3cbf549e32f8630252a.patch Resolves: RHEL-212160 This commit was backported by Ymir, a Red Hat Enterprise Linux software maintenance AI agent. Assisted-by: Ymir --- CVE-2026-58010.patch | 128 +++++++++++++++++++++++++++++++++++++++++++ glib2.spec | 3 + 2 files changed, 131 insertions(+) create mode 100644 CVE-2026-58010.patch diff --git a/CVE-2026-58010.patch b/CVE-2026-58010.patch new file mode 100644 index 0000000..e37ba0c --- /dev/null +++ b/CVE-2026-58010.patch @@ -0,0 +1,128 @@ +From 9aeaf880a1434139accc85337dac6e55c40188e0 Mon Sep 17 00:00:00 2001 +From: Philip Withnall +Date: Sun, 29 Mar 2026 19:10:41 +0100 +Subject: [PATCH 1/2] gvariant: Fix an off-by-one error in an offset comparison +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +This allows a single byte out-of-bounds read off the end of the +(potentially untrusted) byte array backing a `GVariant` when it’s +being checked for normal form. + +I can’t see how this could practically be exploited, but it’s certainly +a security bug as the `GVariant` normal form checking code is supposed +to be robust to malicious inputs. + +Spotted by linhlhq as #YWH-PGM9867-190, and fix and reproducer provided +by them too, thanks. Confirmed and turned into a unit test by me. + +Signed-off-by: Philip Withnall + +Fixes: #3915 +--- + glib/gvariant-serialiser.c | 2 +- + glib/tests/gvariant.c | 48 ++++++++++++++++++++++++++++++++++++++ + 2 files changed, 49 insertions(+), 1 deletion(-) + +diff --git a/glib/gvariant-serialiser.c b/glib/gvariant-serialiser.c +index 9a2975b33..85f28cdce 100644 +--- a/glib/gvariant-serialiser.c ++++ b/glib/gvariant-serialiser.c +@@ -1248,7 +1248,7 @@ gvs_tuple_is_normal (GVariantSerialised value) + + while (offset & alignment) + { +- if (offset > value.size || value.data[offset] != '\0') ++ if (offset >= value.size || value.data[offset] != '\0') + return FALSE; + offset++; + } +diff --git a/glib/tests/gvariant.c b/glib/tests/gvariant.c +index c24cd2f3e..0d59779ed 100644 +--- a/glib/tests/gvariant.c ++++ b/glib/tests/gvariant.c +@@ -5646,6 +5646,52 @@ test_normal_checking_tuple_offsets5 (void) + g_variant_unref (variant); + } + ++/* This is a regression test that looping over the padding bytes in a short ++ * (non-normal) tuple doesn’t overflow the input data. ++ * ++ * See https://gitlab.gnome.org/GNOME/glib/-/issues/3915 */ ++static void ++test_normal_checking_tuple_offsets6 (void) ++{ ++ /* ++ * Type: (ynqiuxthdsog) — 12 members, first member 'y' (byte) has ++ * alignment 0, second 'n' (int16) has alignment 1. ++ * With 1 byte of data (0x28), after reading the first byte member, ++ * offset=1, alignment check for 'n' requires offset to be even, ++ * so the while loop checks value.data[1] — but size is only 1. ++ * ++ * Use heap allocation via GBytes so ASan reports heap-buffer-overflow. ++ */ ++ uint8_t *heap_data = NULL; ++ GBytes *bytes = NULL; ++ const GVariantType *data_type = G_VARIANT_TYPE ("(ynqiuxthdsog)"); ++ GVariant *variant = NULL; ++ GVariant *normal_variant = NULL; ++ GVariant *expected = NULL; ++ ++ g_test_bug ("https://gitlab.gnome.org/GNOME/glib/-/issues/3915"); ++ ++ heap_data = g_malloc (1); ++ heap_data[0] = 0x28; ++ bytes = g_bytes_new_take (heap_data, 1); ++ ++ variant = g_variant_new_from_bytes (data_type, bytes, FALSE); ++ g_assert_nonnull (variant); ++ ++ g_assert_false (g_variant_is_normal_form (variant)); ++ ++ normal_variant = g_variant_get_normal_form (variant); ++ g_assert_nonnull (normal_variant); ++ ++ expected = g_variant_new_parsed ("(byte 0x28, int16 0, uint16 0, 0, uint32 0, int64 0, uint64 0, handle 0, 0.0, '', objectpath '/', signature '')"); ++ g_assert_cmpvariant (expected, variant); ++ g_assert_cmpvariant (expected, normal_variant); ++ ++ g_variant_unref (expected); ++ g_variant_unref (normal_variant); ++ g_variant_unref (variant); ++} ++ + /* Test that an otherwise-valid serialised GVariant is considered non-normal if + * its offset table entries are too wide. + * +@@ -5899,6 +5945,8 @@ main (int argc, char **argv) + test_normal_checking_tuple_offsets4); + g_test_add_func ("/gvariant/normal-checking/tuple-offsets5", + test_normal_checking_tuple_offsets5); ++ g_test_add_func ("/gvariant/normal-checking/tuple-offsets6", ++ test_normal_checking_tuple_offsets6); + g_test_add_func ("/gvariant/normal-checking/tuple-offsets/minimal-sized", + test_normal_checking_tuple_offsets_minimal_sized); + g_test_add_func ("/gvariant/normal-checking/empty-object-path", + +From 10b4d8d5679f49dfc68bb6b24656b18c7e8c588e Mon Sep 17 00:00:00 2001 +From: RHEL Packaging Agent +Date: Thu, 20 Aug 2026 20:16:27 +0000 +Subject: [PATCH 2/2] Include stdint.h for uint8_t in gvariant test + +--- + glib/tests/gvariant.c | 1 + + 1 file changed, 1 insertion(+) + +diff --git a/glib/tests/gvariant.c b/glib/tests/gvariant.c +index 0d59779ed..9f5b2d582 100644 +--- a/glib/tests/gvariant.c ++++ b/glib/tests/gvariant.c +@@ -18,6 +18,7 @@ + #include "config.h" + + #include ++#include + #include + #include + #include diff --git a/glib2.spec b/glib2.spec index 70aeaa3..60f16b8 100644 --- a/glib2.spec +++ b/glib2.spec @@ -68,6 +68,9 @@ Patch: CVE-2026-15588.patch # https://gitlab.gnome.org/GNOME/glib/-/merge_requests/5131 Patch: CVE-2026-58011.patch +# https://gitlab.gnome.org/GNOME/glib/-/merge_requests/5129 +Patch: CVE-2026-58010.patch + BuildRequires: gcc BuildRequires: gcc-c++ BuildRequires: gettext