CVE-2026-6429

Publication date 29 April 2026

Last updated 22 May 2026

Ubuntu priority

Cvss 3 Severity Score

Description

When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances.

Read the notes from the security team

Mitigation

Avoid using the combination netrc, HTTP and HTTP proxy.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
curl	26.04 LTS resolute	Fixed 8.18.0-1ubuntu2.1
	25.10 questing	Fixed 8.14.1-2ubuntu1.3
	24.04 LTS noble	Fixed 8.5.0-2ubuntu10.9
	22.04 LTS jammy	Fixed 7.81.0-1ubuntu1.24
	20.04 LTS focal	Vulnerable
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Vulnerable

Notes

ebarretto

Introduced-in: https://github.com/curl/curl/commit/01165e08e0d131b399fb

Patch details

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

Package	Patch details
curl	Upstream: b4024bf

Severity score breakdown

Parameter	Value
Base score	5.3 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	None
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-8227-1
curl vulnerabilities
4 May 2026