Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3973
Advisory Released Date: 2026-10-12
Advisory Updated Date: 2026-10-12
urllib3 is an HTTP client library for Python. From 1.10.3 until 2.8.0, the HTTPResponse.read_chunked and HTTPResponse.stream methods can allocate unbounded memory because the streaming chunk parser buffers the chunk-size field until newline or EOF without a length bound. The trigger is that a malicious server returns Transfer-Encoding: chunked followed by a very long run of bytes without a newline. The attack mechanism is that a malicious HTTP server sends a very long unterminated chunk-size line. The impact is that unbounded memory allocation can exhaust the client process. This issue is fixed in version 2.8.0. (CVE-2026-97689)
Affected Packages:
python-urllib3
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update python-urllib3 or yum update --advisory ALAS2-2026-3973 to update your system.
noarch:
python-urllib3-1.25.9-1.amzn2.0.11.noarch
src:
python-urllib3-1.25.9-1.amzn2.0.11.src