Resource exhaustion in OpenBSD Libressl
CVE-2026-118374
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.002 (11.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
The 30-day trend appears once there are two daily scores.
Affected products
Weakness classification (CWE)
References
- github.com/openbsd/src/commit/bf5da63f53179ef423d18c56d6da89eaefb56228 (patch)
- github.com/openbsd/src/commit/de4274c56c9ace88232591d4c919d79281a8de59 (patch)
- github.com/openbsd/src/blob/f6f428241d469cf434e60b73fc834d0448f068d5/usr.sbin/o… (technical-description)
- ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-4.4.0-relnotes.txt (release-notes)
- github.com/libressl/portable (product)
- www.vulncheck.com/advisories/libressl-ocspcheck-through-4.4.0-memory-exhaustion… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-118374?
- CVE-2026-118374 is a medium-severity vulnerability in OpenBSD Libressl, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.9/10. Published 2026-10-28.
- How severe is CVE-2026-118374?
- Medium severity. CVSS v3 base score is 5.9 out of 10.