CVE-2026-118768: Botan: CLI utility `ocsp_check` accepts unauthenticated responses
Botan is a C++ cryptography library. From 1.11.34 until 3.13.0, the botan ocspcheck command requested an OCSP response from a certificate's Authority Information Access URL without verifying the response signature or authorizing the signer. A malicious responder or on-path attacker could return a matching and timely GOOD response with an empty, invalid, or unauthorized signature, causing a revoked certificate to produce exit status 0 and OCSP check OK output. Only the command-line interface is affected. This issue is fixed in version 3.13.0.
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Botanto a version that resolves this vulnerability.Fixed in 3.13.0
Event History
Frequently Asked Questions
Who is exposed to this issue?
Only users or automation that invoke Botan's ocsp_check command-line utility are affected. The vulnerability does not affect other Botan library interfaces according to the available information.
What does an attacker need to exploit it?
An attacker must be able to act as the OCSP responder or interfere with the connection to the certificate's Authority Information Access URL. They must return a matching, timely OCSP response indicating GOOD; the response signature may be empty, invalid, or from an unauthorized signer.
How can this affect certificate-revocation checks?
A revoked certificate can be reported as valid: ocsp_check may return exit status 0 and print OCSP check OK after accepting the forged GOOD response. This can cause scripts or operational checks that rely on that command's result to incorrectly accept a revoked certificate.
What versions should be remediated?
The issue affects versions from 1.11.34 until 3.13.0 and is fixed in Botan 3.13.0. Upgrade to version 3.13.0 to obtain the fix.