Vulnerability in libcurl's Public Key Verification for QUIC Connections
CVE-2025-13034

5.9MEDIUM

Key Information:

Vendor

Curl

Status
Curl
Vendor
CVE Published:
8 January 2026

What is CVE-2025-13034?

A vulnerability in libcurl arises from a failure to properly verify the public key of a server certificate when using the CURLOPT_PINNEDPUBLICKEY option or the --pinnedpubkey curl command. This issue is particularly notable when connections are made using QUIC with ngtcp2 linked to GnuTLS, and when users explicitly disable standard certificate verification. By skipping this essential verification step, libcurl allows the possibility of connecting to an impostor server without detection, raising significant security concerns.

Affected Version(s)

curl 8.17.0

curl 8.16.0

curl 8.15.0

References

https://curl.se/docs/CVE-2025-13034.json
https://curl.se/docs/CVE-2025-13034.html

CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Stanislav Fort (Aisle Research)
Daniel Stenberg
.