What is CVE-2026-118373?

CVE-2026-118373 is a low-severity vulnerability in OpenBSD Libressl, classified under Cleartext Transmission of Sensitive Information. CVSS score: 3.7/10. Published 2026-10-28.

How severe is CVE-2026-118373?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in OpenBSD Libressl

CVE-2026-118373

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.

Published 2026-10-28 · last modified 2026-10-28.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.001 (0.4th percentile), scored 2026-10-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 0th percentile — 0.4% 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

OpenBSD Libressl

Weakness classification (CWE)

CWE-319 — Cleartext Transmission of Sensitive Information

References

github.com/openbsd/src/commit/0f7039667044d1cd252cc72134e499186da4da25 (patch)
github.com/openbsd/src/blob/17a8e44328ee2505d69723a126a390a526e50370/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-cleartext-transmi… (third-party-advisory)

Frequently asked questions

What is CVE-2026-118373?: CVE-2026-118373 is a low-severity vulnerability in OpenBSD Libressl, classified under Cleartext Transmission of Sensitive Information. CVSS score: 3.7/10. Published 2026-10-28.
How severe is CVE-2026-118373?: Low severity. CVSS v3 base score is 3.7 out of 10.