Vulnerability · Published Oct 28, 2026 · Assigned by VulnCheck
CVE-2026-118373LibreSSL ocspcheck through 4.4.0 Cleartext Transmission of OCSP Requests via url2host()
Low 3.7
In plain English
A low-severity security flaw 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 0.1% (higher than 0% of all known vulnerabilities).
Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)<0.1%top 99.6% 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 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.
Affected products (as reported)
Weakness: CWE-319 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://github.com/openbsd/src/commit/0f7039667044d1cd252cc72134e499186da4da25 patch
- https://github.com/openbsd/src/blob/17a8e44328ee2505d69723a126a390a526e50370/usr.sbin/ocspcheck/http.c#L299 technical-description
- LibreSSL 4.4.0 Release Notes release-notes
- https://github.com/libressl/portable product
- VulnCheck Advisory: LibreSSL ocspcheck through 4.4.0 Cleartext Transmission of OCSP Requests via url2host() third-party-advisory