CVE-2026-86409

Publication date 14 October 2026

Last updated 14 October 2026

Description

Setting `CURLOPT_AWS_SIGV4` to NULL does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL is set next, leaking state information.

Why is this CVE low priority?

Upstream defined this as low severity

Learn more about Ubuntu priority

Status

Show unmaintained releases

Package	Ubuntu Release	Status
curl	26.04 LTS resolute	Fixed 8.18.0-1ubuntu2.8
	24.04 LTS noble	Vulnerable
	22.04 LTS jammy	Vulnerable
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Patch details

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

Package	Patch details
curl	Upstream: c3c7044

References

Related Ubuntu Security Notices (USN)

USN-8927-1
curl vulnerabilities
14 October 2026

USN-8932-1
curl vulnerabilities
14 October 2026