CVE-2026-97689

urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

CVE-2026-97689 is fixed in 15 products on 1 platform, first by python3-urllib3 2.6.3-1ubuntu1.2, released September 29, 2026. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
7.5
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0034
26th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
python-urllib3 · Debian 14 2.8.0-1 DEBIAN-CVE-2026-97689 Sep 30, 2026
python-urllib3 · RHEL 10 1.26.19-4.el10_2.2 RHSA-2026:85930 Sep 29, 2026
python-urllib3 · Ubuntu 18.04.6 LTS (bionic) 1.22-1ubuntu0.18.04.2+esm5 python-urllib3 1.22-1ubuntu0.18.04.2+esm5 Oct 19, 2026
python-urllib3 · opensuse-leap 16.0 2.5.0-160000.8.1 OPENSUSE-SU-2026:22071-1 Nov 7, 2026
python-urllib3 · rocky 10 0:1.26.19-4.el10_2.2 RLSA-2026:85930 Nov 7, 2026
python-urllib3 · rocky 8 0:1.24.2-11.el8_10 RLSA-2026:90759 Nov 7, 2026
python-urllib3 · rocky 9 0:1.26.5-8.el9_8.2 RLSA-2026:90494 Nov 7, 2026
python-urllib3 · sles 15.6 2.0.7-150400.7.36.1 SUSE-SU-2026:4704-1 Nov 7, 2026
python-urllib3 · sles 15.7 2.0.7-150400.7.36.1 SUSE-SU-2026:4704-1 Nov 7, 2026
python-urllib3 · sles 16.0 2.5.0-160000.8.1 SUSE-SU-2026:24217-1 Nov 7, 2026
python-urllib3_1 · sles 15.6 1.26.18-150600.3.14.1 SUSE-SU-2026:4948-1 Nov 7, 2026
python-urllib3_1 · sles 15.7 1.26.18-150600.3.14.1 SUSE-SU-2026:4948-1 Nov 7, 2026
python3-pip · amzn 2023 21.3.1-2.amzn2023.0.22 ALAS2023-2026-3175 Nov 7, 2026
python3-pip-wheel · amzn 2023 21.3.1-2.amzn2023.0.22 ALAS2023-2026-3175 Nov 7, 2026
python3-urllib3 · RHEL 8 0:1.24.2-11.el8_10 RHSA-2026:90759 Oct 29, 2026
python3-urllib3 · RHEL 9 0:1.26.5-8.el9_8.2 RHSA-2026:90494 Oct 29, 2026
python3-urllib3 · Ubuntu 18.04.6 LTS (bionic) 1.22-1ubuntu0.18.04.2+esm5 python3-urllib3 1.22-1ubuntu0.18.04.2+esm5 Oct 19, 2026
python3-urllib3 · Ubuntu 20.04 LTS (focal) 1.25.8-2ubuntu0.4+esm6 python3-urllib3 1.25.8-2ubuntu0.4+esm6 Oct 19, 2026
python3-urllib3 · Ubuntu 22.04.1 LTS (jammy) 1.26.5-1~exp1ubuntu0.8 python3-urllib3 1.26.5-1~exp1ubuntu0.8 Oct 19, 2026
python3-urllib3 · Ubuntu 24.04.5 LTS (noble) 2.0.7-1ubuntu0.8 python3-urllib3 2.0.7-1ubuntu0.8 Oct 19, 2026
python3-urllib3 · Ubuntu 26.04.1 LTS (resolute) 2.6.3-1ubuntu1.2 python3-urllib3 2.6.3-1ubuntu1.2 Sep 29, 2026
python3-urllib3 · almalinux 10 1.26.19-4.el10_2.2 ALSA-2026:85930 Nov 7, 2026
python3-urllib3 · almalinux 8 1.24.2-11.el8_10 ALSA-2026:90759 Nov 7, 2026
python3-urllib3 · almalinux 9 1.26.5-8.el9_8.2 ALSA-2026:90494 Nov 7, 2026
python3-urllib3 · amzn 2023 1.25.10-5.amzn2023.0.9 ALAS2023-2026-3184 Nov 7, 2026
python3-urllib3 · ol 10 0:1.26.19-4.el10_2.2 ELSA-2026-85930 Nov 7, 2026
python3-urllib3 · ol 8 0:1.24.2-11.el8_10 ELSA-2026-90759 Nov 7, 2026
python3-urllib3 · ol 9 0:1.26.5-8.el9_8.2 ELSA-2026-90494 Nov 7, 2026
python3.11-pip · amzn 2023 22.3.1-2.amzn2023.0.15 ALAS2023-2026-3174 Nov 7, 2026
python3.11-pip-wheel · amzn 2023 22.3.1-2.amzn2023.0.15 ALAS2023-2026-3174 Nov 7, 2026
python3.12-pip · amzn 2023 23.2.1-4.amzn2023.0.12 ALAS2023-2026-3173 Nov 7, 2026
python3.12-pip-wheel · amzn 2023 23.2.1-4.amzn2023.0.12 ALAS2023-2026-3173 Nov 7, 2026
python3.12-urllib3 · RHEL 8 0:1.26.19-5.el8_10 RHSA-2026:92474 Oct 30, 2026
python3.12-urllib3 · RHEL 9 0:1.26.19-3.el9_8.2 RHSA-2026:85929 Oct 21, 2026
python3.12-urllib3 · almalinux 8 1.26.19-5.el8_10 ALSA-2026:92474 Nov 7, 2026
python3.12-urllib3 · almalinux 9 1.26.19-3.el9_8.2 ALSA-2026:85929 Nov 7, 2026
python3.12-urllib3 · ol 8 0:1.26.19-5.el8_10 ELSA-2026-92474 Nov 7, 2026
python3.12-urllib3 · ol 9 0:1.26.19-3.el9_8.2 ELSA-2026-85929 Nov 7, 2026
python3.12-urllib3 · rocky 8 0:1.26.19-5.el8_10 RLSA-2026:92474 Nov 7, 2026
python3.12-urllib3 · rocky 9 0:1.26.19-3.el9_8.2 RLSA-2026:85929 Nov 7, 2026
python3.13-pip · amzn 2023 24.2-259.amzn2023.0.9 ALAS2023-2026-3172 Nov 7, 2026
python3.13-pip-wheel · amzn 2023 24.2-259.amzn2023.0.9 ALAS2023-2026-3172 Nov 7, 2026
python3.14-pip · amzn 2023 26.1.1-1.amzn2023.0.4 ALAS2023-2026-3171 Nov 7, 2026
python3.14-pip-wheel · amzn 2023 26.1.1-1.amzn2023.0.4 ALAS2023-2026-3171 Nov 7, 2026
python3.14-urllib3 · RHEL 10 2.6.3-2.el10_2.6 RHSA-2026:84578 Oct 19, 2026
python3.14-urllib3 · RHEL 9 0:2.6.3-2.el9_8.6 RHSA-2026:84577 Oct 19, 2026
python3.14-urllib3 · almalinux 10 2.6.3-2.el10_2.6 ALSA-2026:84578 Nov 7, 2026
python3.14-urllib3 · almalinux 9 2.6.3-2.el9_8.6 ALSA-2026:84577 Nov 7, 2026
python3.14-urllib3 · ol 10 0:2.6.3-2.el10_2.6 ELSA-2026-84578 Nov 7, 2026
python3.14-urllib3 · ol 9 0:2.6.3-2.el9_8.6 ELSA-2026-84577 Nov 7, 2026
python3.14-urllib3 · rocky 10 0:2.6.3-2.el10_2.6 RLSA-2026:84578 Nov 7, 2026
python3.14-urllib3 · rocky 9 0:2.6.3-2.el9_8.6 RLSA-2026:84577 Nov 7, 2026

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