Security fixes for CVE-2025-66471 and CVE-2025-66418

CVE-2025-66418.patch

@@ -0,0 +1,75 @@
+From dbb1dc2ef9a6c36e7b9139151d4db2ffab69eceb Mon Sep 17 00:00:00 2001
+From: Illia Volochii <illia.volochii@gmail.com>
+Date: Fri, 5 Dec 2025 16:41:33 +0200
+Subject: [PATCH] Security fix for CVE-2025-66418
+
+* Add a hard-coded limit for the decompression chain
+
+* Reuse new list
+
+(cherry picked from commit 24d7b67eac89f94e11003424bcf0d8f7b72222a8)
+---
+ changelog/GHSA-gm62-xv2j-4w53.security.rst |  4 ++++
+ src/urllib3/response.py                    | 12 +++++++++++-
+ test/test_response.py                      | 10 ++++++++++
+ 3 files changed, 25 insertions(+), 1 deletion(-)
+ create mode 100644 changelog/GHSA-gm62-xv2j-4w53.security.rst
+
+diff --git a/changelog/GHSA-gm62-xv2j-4w53.security.rst b/changelog/GHSA-gm62-xv2j-4w53.security.rst
+new file mode 100644
+index 00000000..6646eaa3
+--- /dev/null
++++ b/changelog/GHSA-gm62-xv2j-4w53.security.rst
+@@ -0,0 +1,4 @@
++Fixed a security issue where an attacker could compose an HTTP response with
++virtually unlimited links in the ``Content-Encoding`` header, potentially
++leading to a denial of service (DoS) attack by exhausting system resources
++during decoding. The number of allowed chained encodings is now limited to 5.
+diff --git a/src/urllib3/response.py b/src/urllib3/response.py
+index 60bd98c9..ba366eef 100644
+--- a/src/urllib3/response.py
++++ b/src/urllib3/response.py
+@@ -163,8 +163,18 @@ class MultiDecoder(object):
+         they were applied.
+     """
+ 
++    # Maximum allowed number of chained HTTP encodings in the
++    # Content-Encoding header.
++    max_decode_links = 5
++
+     def __init__(self, modes):
+-        self._decoders = [_get_decoder(m.strip()) for m in modes.split(',')]
++        encodings = [m.strip() for m in modes.split(",")]
++        if len(encodings) > self.max_decode_links:
++            raise DecodeError(
++                "Too many content encodings in the chain: "
++                f"{len(encodings)} > {self.max_decode_links}"
++            )
++        self._decoders = [_get_decoder(e) for e in encodings]
+ 
+     def flush(self):
+         return self._decoders[0].flush()
+diff --git a/test/test_response.py b/test/test_response.py
+index 347276e8..bd083b7f 100644
+--- a/test/test_response.py
++++ b/test/test_response.py
+@@ -467,6 +467,16 @@ class TestResponse(object):
+         assert r.read(9 * 37) == b"foobarbaz" * 37
+         assert r.read() == b""
+ 
++    def test_read_multi_decoding_too_many_links(self):
++        fp = BytesIO(b"foo")
++        with pytest.raises(
++            DecodeError, match="Too many content encodings in the chain: 6 > 5"
++        ):
++            HTTPResponse(
++                fp,
++                headers={"content-encoding": "gzip, deflate, br, zstd, gzip, deflate"},
++            )
++
+     def test_body_blob(self):
+         resp = HTTPResponse(b'foo')
+         assert resp.data == b'foo'
+-- 
+2.52.0
+

python-urllib3.spec

@@ -2,7 +2,7 @@
 
 Name:           python-%{srcname}
 Version:        1.24.2
-Release:        8%{?dist}
+Release:        9%{?dist}
 Summary:        Python HTTP library with thread-safe connection pooling and file post
 
 License:        MIT
@@ -55,6 +55,9 @@ Patch5: CVE-2023-45803.patch
 # Upstream fix: https://github.com/urllib3/urllib3/commit/40b6d1605814dd1db0a46e202d6e56f2e4c9a468
 Patch6: CVE-2024-37891.patch
 
+Patch7: CVE-2025-66471.patch
+Patch8: CVE-2025-66418.patch
+
 %description
 Python HTTP module with connection pooling and file POST abilities.
 
@@ -87,6 +90,8 @@ Python3 HTTP module with connection pooling and file POST abilities.
 %patch4 -p1
 %patch5 -p1
 %patch6 -p1
+%patch7 -p1
+%patch8 -p1
 
 # Make sure that the RECENT_DATE value doesn't get too far behind what the current date is.
 # RECENT_DATE must not be older that 2 years from the build time, or else test_recent_date
@@ -162,6 +167,11 @@ popd
 
 
 %changelog
+* Wed Dec 17 2025 Miro Hrončok <mhroncok@redhat.com> - 1.24.2-9
+- Security fix for CVE-2025-66471
+- Security fix for CVE-2025-66418
+Resolves: RHEL-139410
+
 * Mon Jul 01 2024 Lumír Balhar <lbalhar@redhat.com> - 1.24.2-8
 - Security fix for CVE-2024-37891
 Resolves: RHEL-45334