CVE-2026-44431

Description

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
python-urllib3	26.04 LTS resolute	Fixed 2.6.3-1ubuntu1.1
	25.10 questing	Fixed 2.3.0-3ubuntu0.6
	24.04 LTS noble	Fixed 2.0.7-1ubuntu0.7
	22.04 LTS jammy	Fixed 1.26.5-1~exp1ubuntu0.7
	20.04 LTS focal	Fixed 1.25.8-2ubuntu0.4+esm5
	18.04 LTS bionic	Fixed 1.22-1ubuntu0.18.04.2+esm4
	16.04 LTS xenial	Fixed 1.13.1-2ubuntu0.16.04.4+esm4
	14.04 LTS trusty	Ignored changes too intrusive
python-pip	26.04 LTS resolute	Needs evaluation
	25.10 questing	Ignored end of life, was needs-triage
	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	Upstream: 5ec0de4
python-pip	Upstream: 5ec0de4

Severity score breakdown

CVSS version:

Base score 8.2 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Attack requirements	Present
Privileges required	None
User interaction	None
Vulnerable system - Confidentiality impact	High
Vulnerable system - Integrity impact	None
Vulnerable system - Availability impact	None
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	None
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	8.2 · High
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

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

Base score 5.3 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	Low
Integrity impact	None
Availability impact	None

Scores

Parameter	Value
Base score	5.3 · Medium
Exploitability score	-
Impact score	-

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

References

Related Ubuntu Security Notices (USN)

USN-8379-1
urllib3 vulnerabilities
3 June 2026

USN-8811-1
urllib3 vulnerability
24 September 2026