CVE-2026-118374
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk11th percentile - higher than 11% of all known CVEs
Summary
LibreSSL ocspcheck through 4.4.0 contains a memory exhaustion vulnerability that allows malicious OCSP responders to exhaust memory by sending unbounded HTTP responses. Attackers controlling the responder or intercepting plain HTTP AIA OCSP traffic can stream endless headers or body data to http_head_read() and http_body_read(), denying certificate status checks.
Risk Assessment
This may prevent certificate revocation status verification, leading to denial of service or acceptance of revoked certificates.
Recommendation
Update LibreSSL to a patched version and consider enforcing OCSP over HTTPS to make traffic interception harder.
Other vulnerabilities in LibreSSL ocspcheck
See all- CVE-2026-118373Low
LibreSSL ocspcheck through 4.4.0 contains a cleartext transmission vulnerability because url2host() discards the OCSP URL scheme and http_alloc() only selects TLS for port 443. On-path network attackers can read OCSP requests sent to https responder URLs on non-443 ports, exposing certificate serial numbers, issuer hashes, and nonces.
- CVE-2026-118372Low
LibreSSL ocspcheck through 4.4.0 contains a CRLF injection vulnerability that allows attackers to inject HTTP headers by embedding CR/LF sequences in a certificate's AIA OCSP URI path. Because url2host() copies the path without rejecting control characters and http_open() places it in the POST request line, attackers can inject headers or split OCSP requests sent to the responder host.
Original NVD description (English source)
LibreSSL ocspcheck through 4.4.0 contains a memory exhaustion vulnerability that allows malicious OCSP responders to exhaust memory by sending unbounded HTTP responses. Attackers controlling the responder or intercepting plain HTTP AIA OCSP traffic can stream endless headers or body data to http_head_read() and http_body_read(), denying certificate status checks.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS