Protection Mechanism Failure in cURL - CVE-2025-13034
Published: January 7, 2026
Vulnerability identifier: #VU121024
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2025-13034
CWE-ID: CWE-693
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: curl.haxx.se
Affected software:
cURL
cURL
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to insufficient implementation of security measures. When using CURLOPT_PINNEDPUBLICKEY option with libcurl or --pinnedpubkey with the curl tool, curl should check the public key of the server certificate to verify the peer. This check was skipped in a certain condition that would then make curl allow the connection without performing the proper check, thus not noticing a possible impostor.
To skip this check, the connection had to be done with QUIC with ngtcp2 built to use GnuTLS and the user had to explicitly disable the standard certificate verifiation.
How to mitigate CVE-2025-13034
Install updates from vendor's website.