# 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. - Web page: https://patchblox.com/security/cve/CVE-2026-97689 - Priority: High - CVSS: 7.5 (Important) - EPSS: 0.0034 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 29, 2026 - Weakness: Allocation of Resources Without Limits or Throttling - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97689 ## Description 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 | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | python-urllib3 Debian 14 | 2.8.0-1 | [DEBIAN-CVE-2026-97689](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97689.md) | Sep 30, 2026 | | Linux | python-urllib3 RHEL 10 | 1.26.19-4.el10_2.2 | [RHSA-2026:85930](https://patchblox.com/security/data/fix/linux/rhsa-2026-85930.md) | Sep 29, 2026 | | Linux | python-urllib3 Ubuntu 18.04.6 LTS (bionic) | 1.22-1ubuntu0.18.04.2+esm5 | [python-urllib3 1.22-1ubuntu0.18.04.2+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-urllib3-1.22-1ubuntu0.18.04.2-esm5.md) | Oct 19, 2026 | | Linux | python-urllib3 opensuse-leap 16.0 | 2.5.0-160000.8.1 | [OPENSUSE-SU-2026:22071-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22071-1.md) | Nov 7, 2026 | | Linux | python-urllib3 rocky 10 | 0:1.26.19-4.el10_2.2 | [RLSA-2026:85930](https://patchblox.com/security/data/fix/linux/rlsa-2026-85930.md) | Nov 7, 2026 | | Linux | python-urllib3 rocky 8 | 0:1.24.2-11.el8_10 | [RLSA-2026:90759](https://patchblox.com/security/data/fix/linux/rlsa-2026-90759.md) | Nov 7, 2026 | | Linux | python-urllib3 rocky 9 | 0:1.26.5-8.el9_8.2 | [RLSA-2026:90494](https://patchblox.com/security/data/fix/linux/rlsa-2026-90494.md) | Nov 7, 2026 | | Linux | python-urllib3 sles 15.6 | 2.0.7-150400.7.36.1 | [SUSE-SU-2026:4704-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4704-1.md) | Nov 7, 2026 | | Linux | python-urllib3 sles 15.7 | 2.0.7-150400.7.36.1 | [SUSE-SU-2026:4704-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4704-1.md) | Nov 7, 2026 | | Linux | python-urllib3 sles 16.0 | 2.5.0-160000.8.1 | [SUSE-SU-2026:24217-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24217-1.md) | Nov 7, 2026 | | Linux | python-urllib3_1 sles 15.6 | 1.26.18-150600.3.14.1 | [SUSE-SU-2026:4948-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4948-1.md) | Nov 7, 2026 | | Linux | python-urllib3_1 sles 15.7 | 1.26.18-150600.3.14.1 | [SUSE-SU-2026:4948-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4948-1.md) | Nov 7, 2026 | | Linux | python3-pip amzn 2023 | 21.3.1-2.amzn2023.0.22 | [ALAS2023-2026-3175](https://patchblox.com/security/data/fix/linux/alas2023-2026-3175.md) | Nov 7, 2026 | | Linux | python3-pip-wheel amzn 2023 | 21.3.1-2.amzn2023.0.22 | [ALAS2023-2026-3175](https://patchblox.com/security/data/fix/linux/alas2023-2026-3175.md) | Nov 7, 2026 | | Linux | python3-urllib3 RHEL 8 | 0:1.24.2-11.el8_10 | [RHSA-2026:90759](https://patchblox.com/security/data/fix/linux/rhsa-2026-90759.md) | Oct 29, 2026 | | Linux | python3-urllib3 RHEL 9 | 0:1.26.5-8.el9_8.2 | [RHSA-2026:90494](https://patchblox.com/security/data/fix/linux/rhsa-2026-90494.md) | Oct 29, 2026 | | Linux | python3-urllib3 Ubuntu 18.04.6 LTS (bionic) | 1.22-1ubuntu0.18.04.2+esm5 | [python3-urllib3 1.22-1ubuntu0.18.04.2+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-urllib3-1.22-1ubuntu0.18.04.2-esm5.md) | Oct 19, 2026 | | Linux | python3-urllib3 Ubuntu 20.04 LTS (focal) | 1.25.8-2ubuntu0.4+esm6 | [python3-urllib3 1.25.8-2ubuntu0.4+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-urllib3-1.25.8-2ubuntu0.4-esm6.md) | Oct 19, 2026 | | Linux | python3-urllib3 Ubuntu 22.04.1 LTS (jammy) | 1.26.5-1~exp1ubuntu0.8 | [python3-urllib3 1.26.5-1~exp1ubuntu0.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-urllib3-1.26.5-1-exp1ubuntu0.8.md) | Oct 19, 2026 | | Linux | python3-urllib3 Ubuntu 24.04.5 LTS (noble) | 2.0.7-1ubuntu0.8 | [python3-urllib3 2.0.7-1ubuntu0.8](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-urllib3-2.0.7-1ubuntu0.8.md) | Oct 19, 2026 | | Linux | python3-urllib3 Ubuntu 26.04.1 LTS (resolute) | 2.6.3-1ubuntu1.2 | [python3-urllib3 2.6.3-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-urllib3-2.6.3-1ubuntu1.2.md) | Sep 29, 2026 | | Linux | python3-urllib3 almalinux 10 | 1.26.19-4.el10_2.2 | [ALSA-2026:85930](https://patchblox.com/security/data/fix/linux/alsa-2026-85930.md) | Nov 7, 2026 | | Linux | python3-urllib3 almalinux 8 | 1.24.2-11.el8_10 | [ALSA-2026:90759](https://patchblox.com/security/data/fix/linux/alsa-2026-90759.md) | Nov 7, 2026 | | Linux | python3-urllib3 almalinux 9 | 1.26.5-8.el9_8.2 | [ALSA-2026:90494](https://patchblox.com/security/data/fix/linux/alsa-2026-90494.md) | Nov 7, 2026 | | Linux | python3-urllib3 amzn 2023 | 1.25.10-5.amzn2023.0.9 | [ALAS2023-2026-3184](https://patchblox.com/security/data/fix/linux/alas2023-2026-3184.md) | Nov 7, 2026 | | Linux | python3-urllib3 ol 10 | 0:1.26.19-4.el10_2.2 | [ELSA-2026-85930](https://patchblox.com/security/data/fix/linux/elsa-2026-85930.md) | Nov 7, 2026 | | Linux | python3-urllib3 ol 8 | 0:1.24.2-11.el8_10 | [ELSA-2026-90759](https://patchblox.com/security/data/fix/linux/elsa-2026-90759.md) | Nov 7, 2026 | | Linux | python3-urllib3 ol 9 | 0:1.26.5-8.el9_8.2 | [ELSA-2026-90494](https://patchblox.com/security/data/fix/linux/elsa-2026-90494.md) | Nov 7, 2026 | | Linux | python3.11-pip amzn 2023 | 22.3.1-2.amzn2023.0.15 | [ALAS2023-2026-3174](https://patchblox.com/security/data/fix/linux/alas2023-2026-3174.md) | Nov 7, 2026 | | Linux | python3.11-pip-wheel amzn 2023 | 22.3.1-2.amzn2023.0.15 | [ALAS2023-2026-3174](https://patchblox.com/security/data/fix/linux/alas2023-2026-3174.md) | Nov 7, 2026 | | Linux | python3.12-pip amzn 2023 | 23.2.1-4.amzn2023.0.12 | [ALAS2023-2026-3173](https://patchblox.com/security/data/fix/linux/alas2023-2026-3173.md) | Nov 7, 2026 | | Linux | python3.12-pip-wheel amzn 2023 | 23.2.1-4.amzn2023.0.12 | [ALAS2023-2026-3173](https://patchblox.com/security/data/fix/linux/alas2023-2026-3173.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 RHEL 8 | 0:1.26.19-5.el8_10 | [RHSA-2026:92474](https://patchblox.com/security/data/fix/linux/rhsa-2026-92474.md) | Oct 30, 2026 | | Linux | python3.12-urllib3 RHEL 9 | 0:1.26.19-3.el9_8.2 | [RHSA-2026:85929](https://patchblox.com/security/data/fix/linux/rhsa-2026-85929.md) | Oct 21, 2026 | | Linux | python3.12-urllib3 almalinux 8 | 1.26.19-5.el8_10 | [ALSA-2026:92474](https://patchblox.com/security/data/fix/linux/alsa-2026-92474.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 almalinux 9 | 1.26.19-3.el9_8.2 | [ALSA-2026:85929](https://patchblox.com/security/data/fix/linux/alsa-2026-85929.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 ol 8 | 0:1.26.19-5.el8_10 | [ELSA-2026-92474](https://patchblox.com/security/data/fix/linux/elsa-2026-92474.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 ol 9 | 0:1.26.19-3.el9_8.2 | [ELSA-2026-85929](https://patchblox.com/security/data/fix/linux/elsa-2026-85929.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 rocky 8 | 0:1.26.19-5.el8_10 | [RLSA-2026:92474](https://patchblox.com/security/data/fix/linux/rlsa-2026-92474.md) | Nov 7, 2026 | | Linux | python3.12-urllib3 rocky 9 | 0:1.26.19-3.el9_8.2 | [RLSA-2026:85929](https://patchblox.com/security/data/fix/linux/rlsa-2026-85929.md) | Nov 7, 2026 | | Linux | python3.13-pip amzn 2023 | 24.2-259.amzn2023.0.9 | [ALAS2023-2026-3172](https://patchblox.com/security/data/fix/linux/alas2023-2026-3172.md) | Nov 7, 2026 | | Linux | python3.13-pip-wheel amzn 2023 | 24.2-259.amzn2023.0.9 | [ALAS2023-2026-3172](https://patchblox.com/security/data/fix/linux/alas2023-2026-3172.md) | Nov 7, 2026 | | Linux | python3.14-pip amzn 2023 | 26.1.1-1.amzn2023.0.4 | [ALAS2023-2026-3171](https://patchblox.com/security/data/fix/linux/alas2023-2026-3171.md) | Nov 7, 2026 | | Linux | python3.14-pip-wheel amzn 2023 | 26.1.1-1.amzn2023.0.4 | [ALAS2023-2026-3171](https://patchblox.com/security/data/fix/linux/alas2023-2026-3171.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 RHEL 10 | 2.6.3-2.el10_2.6 | [RHSA-2026:84578](https://patchblox.com/security/data/fix/linux/rhsa-2026-84578.md) | Oct 19, 2026 | | Linux | python3.14-urllib3 RHEL 9 | 0:2.6.3-2.el9_8.6 | [RHSA-2026:84577](https://patchblox.com/security/data/fix/linux/rhsa-2026-84577.md) | Oct 19, 2026 | | Linux | python3.14-urllib3 almalinux 10 | 2.6.3-2.el10_2.6 | [ALSA-2026:84578](https://patchblox.com/security/data/fix/linux/alsa-2026-84578.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 almalinux 9 | 2.6.3-2.el9_8.6 | [ALSA-2026:84577](https://patchblox.com/security/data/fix/linux/alsa-2026-84577.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 ol 10 | 0:2.6.3-2.el10_2.6 | [ELSA-2026-84578](https://patchblox.com/security/data/fix/linux/elsa-2026-84578.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 ol 9 | 0:2.6.3-2.el9_8.6 | [ELSA-2026-84577](https://patchblox.com/security/data/fix/linux/elsa-2026-84577.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 rocky 10 | 0:2.6.3-2.el10_2.6 | [RLSA-2026:84578](https://patchblox.com/security/data/fix/linux/rlsa-2026-84578.md) | Nov 7, 2026 | | Linux | python3.14-urllib3 rocky 9 | 0:2.6.3-2.el9_8.6 | [RLSA-2026:84577](https://patchblox.com/security/data/fix/linux/rlsa-2026-84577.md) | Nov 7, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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