Insertion of Sensitive Information Into Sent Data in cURL - CVE-2026-86413
Published: October 14, 2026
Vulnerability identifier: #VU155688
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-86413
CWE-ID: CWE-201
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose Negotiate authentication credentials to an unrelated origin.
The vulnerability exists due to improper restriction of credential forwarding in curl's Negotiate authentication handling when following redirects. A remote attacker can cause a redirect to an unrelated origin using a URL containing a username and password to disclose Negotiate authentication credentials to an unrelated origin.
Exploitation requires an ambient user, configured by supplying a blank username so that curl uses credentials provided by the Kerberos system. The issue only triggers when usernames in URLs are permitted.
Affected software
cURL
How to mitigate CVE-2026-86413
Install security update from vendor's website.
cURL - update to 8.23.0