Vulnerability · Published Oct 28, 2026 · Assigned by VulnCheck

CVE-2026-118374LibreSSL ocspcheck through 4.4.0 Memory Exhaustion via Unbounded OCSP HTTP Response

Medium 5.9

In plain English

A medium-severity resource allocation without limits in LibreSSL from OpenBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.2%top 88.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
OpenBSD	LibreSSL	0 – through 4.4.0

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/openbsd/src/commit/bf5da63f53179ef423d18c56d6da89eaefb56228 patch
https://github.com/openbsd/src/commit/de4274c56c9ace88232591d4c919d79281a8de59 patch
https://github.com/openbsd/src/blob/f6f428241d469cf434e60b73fc834d0448f068d5/usr.sbin/ocspcheck/http.c#L419 technical-description
LibreSSL 4.4.0 Release Notes release-notes
https://github.com/libressl/portable product
VulnCheck Advisory: LibreSSL ocspcheck through 4.4.0 Memory Exhaustion via Unbounded OCSP HTTP Response third-party-advisory