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TI-2026-81661 Aliases CVE-2026-118373GHSA-56qc-c576-qq46

Cleartext transmission of OCSP requests in LibreSSL ocspcheck

Priority LOW 27CWE-319Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-319.

Summary

LibreSSL ocspcheck through 4.4.0 transmits OCSP requests in cleartext when the responder URL uses https on a port other than 443. The URL scheme is discarded, so TLS is selected only for port 443. An on-path network attacker can read certificate serial numbers, issuer hashes, and nonces from these requests (CWE-319).

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0009 0th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
OpenBSDLibreSSLup to 4.4.0—No fix listedCNA
  • LibreSSL VendorOpenBSD Affected up to 4.4.0 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for LibreSSL.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-118373
  2. 2026-10-28 Alias added: GHSA-56qc-c576-qq46
  3. 2026-10-28 Priority changed: MEDIUM → LOW
  4. 2026-11-05 CISA SSVC decision points changed

References

Patch 1

Other 3

  • TI-2020-05854 smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-19792 The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently… CVSS 3.1CRITICAL 9.8
  • TI-2002-00376 Integer overflow in xdr_array function in RPC servers for operating systems that use… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2003-00437 Off-by-one error in the fb_realpath() function, as derived from the realpath function in… CVSS 3.1CRITICAL 9.8
  • TI-2007-05153 Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD… CVSS 2.0HIGH 7.2
See all 369 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences