Low severity · published Oct 28, 2026
CVE-2026-118373
LibreSSL ocspcheck through 4.4.0 Cleartext Transmission of OCSP Requests via url2host()
New
3.7
CVSS
–
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
LibreSSL · OpenBSD
through 4.4.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-118373
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-118373
patch
https://github.com/openbsd/src/commit/0f7039667044d1cd252cc72134e499186da4da25
technical-description
https://github.com/openbsd/src/blob/17a8e44328ee2505d69723a126a390a526e50370/usr.sbin/ocspcheck/http.c#L299
release-notes
https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-4.4.0-relnotes.txt
product
https://github.com/libressl/portable
third-party-advisory
https://www.vulncheck.com/advisories/libressl-ocspcheck-through-4.4.0-cleartext-transmission-of-ocsp-requests-via-url2host
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