CVE-2026-97689

Publication date 29 September 2026

Last updated 14 October 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.5 · High

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
python-urllib3 26.04 LTS resolute
Fixed 2.6.3-1ubuntu1.2
24.04 LTS noble
Fixed 2.0.7-1ubuntu0.8
22.04 LTS jammy
Fixed 1.26.5-1~exp1ubuntu0.8
20.04 LTS focal
Fixed 1.25.8-2ubuntu0.4+esm6
18.04 LTS bionic
Fixed 1.22-1ubuntu0.18.04.2+esm5
16.04 LTS xenial Ignored changes too intrusive
14.04 LTS trusty
Not affected
python-pip 26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

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Notes

mdeslaur

On focal and earlier, the python-pip package bundles python-urllib3 binaries when built. After updating python-urllib3, a no-change rebuild of python-pip is required. On jammy and later, python-urllib3 is bundled in the python-pip package and needs to be patched.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
python-urllib3

Severity score breakdown

CVSS version:

Base score 8.9 · High

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

Base score 7.5 · High

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-8926-1
    • urllib3 vulnerabilities
    • 14 October 2026

Other references

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