Insertion of Sensitive Information Into Sent Data in cURL - CVE-2026-86415
Published: October 14, 2026
Vulnerability identifier: #VU155686
CSH Severity: Low
CVSS v4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-86415
CWE-ID: CWE-201
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to failure to account for the automatic client certificate option in libcurl's connection cache matcher when matching cached connections for transfers redirected to a different origin. A remote attacker can exploit reuse of an already authenticated cached connection despite automatic client certificate selection being disabled for the redirected transfer to disclose sensitive information.
Only builds using the Schannel TLS backend, which is available only on Windows, are affected.
Affected software
cURL
How to mitigate CVE-2026-86415
Install security update from vendor's website.
cURL - update to 8.23.0