CVE-2026-118373: OpenBSD LibreSSL · Cleartext Transmission
Affects OpenBSD LibreSSLSource CVE Database V5
Not known to be exploited · CVSS 6.3 Medium.
Data as of 28 Oct 2026, 02:42 UTC
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| OpenBSDLibreSSL | Affected
| Fixed in– |
GitHubLibreSSLpkg:github/LibreSSLOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, avoid configuring OCSP responders on non-443 ports or use network-level encryption to protect OCSP traffic. Monitor vendor communications for updates.
Description
CVE-2026-118373 is a vulnerability in LibreSSL's ocspcheck component up to version 4.4.0 that causes cleartext transmission of sensitive OCSP request data. The issue arises because the function url2host() removes the OCSP URL scheme, and http_alloc() only uses TLS for port 443. As a result, OCSP requests sent to HTTPS responder URLs on non-443 ports are transmitted without encryption, exposing certificate serial numbers, issuer hashes, and nonces to on-path attackers.
References
- github.com/openbsd/src/commit/0f7039667044d1cd252cc72134e499186da4da25 (opens in a new tab)
- github.com/openbsd/src/blob/17a8e44328ee2505d69723a126a390a526e50370/usr.sbin/ocspcheck/http.c (opens in a new tab)
- ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-4.4.0-relnotes.txt (opens in a new tab)
- github.com/libressl/portable (opens in a new tab)
- vulncheck.com/advisories/libressl-ocspcheck-through-4.4.0-cleartext-transmission-of-ocsp-requests-via-url2host (opens in a new tab)