CVE-2026-80229 – curl

CVSS 7.5 IMPORTANT [2] Critical – Same Day Deployment

“When the library that moves your data can hand one user's session to another, every connection becomes a liability.”

This curl update fixes five vulnerabilities in libcurl that affect memory safety, connection reuse, and TLS trust enforcement. CVE-2026-19931 has a CVSS score of 9.8, Critical severity: libcurl can wrongly reuse a Negotiate-authenticated connection, so one user's request can travel over another user's authenticated session. CVE-2026-18924 has a CVSS score of 9.1, Critical severity: a use-after-free in HTTP/2 Server Push cleanup on shared connections can enable remote code execution and privilege escalation. CVE-2026-80229 has a CVSS score of 7.5, High severity: pooled TLS connections in OpenSSL 3 provider configurations keep a dangling pointer after the easy handle is destroyed, causing a heap use-after-free that can lead to code execution.

CVE-2026-80230 has a CVSS score of 7.5, High severity: libcurl skips public key pinning when peer verification is disabled, letting unauthenticated connections succeed. CVE-2026-82208 has a CVSS score of 7.5, High severity: with the wolfSSL backend, a cached trust store can silently replace a callback-selected one and accept certificates that should be rejected. Proof-of-concept code exists for CVE-2026-18924, CVE-2026-19931, CVE-2026-80230, and CVE-2026-82208. Apply this update promptly to every system and application that bundles libcurl.

Key Details

Affected Product
Haxx Curl
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
CWE Classification
CWE-416
Patch this CVE on all your endpoints in under 5 minutes. First 200 endpoints are free forever, scale as needed.