# CVE-2026-118766: Botan: Online OCSP redirects enable blind requests to internal HTTP services

Status: published. Published: 2026-10-29. Updated: 2026-11-04.

Botan is a C++ cryptography library. Prior to 3.13.0, Botan's online OCSP client allowed a single HTTP redirect while posting an OCSP request to the URI in a certificate's Authority Information Access extension. A malicious OCSP responder or an on-path attacker could redirect the client to make one blind request to an otherwise unreachable internal HTTP service. The primary impact is blind SSRF that might affect internal services with non-idempotent GET handlers, and response timing can provide a coarse internal-service oracle. This issue is fixed in version 3.13.0.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- randombit / botan: < 3.13.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: 0.10% as of 2026-11-03; percentile 0.70%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-918

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/randombit/botan/security/advisories/GHSA-9qgq-q9j4-4f82 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/randombit/botan/pull/5815 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/randombit/botan/commit/9791ca39a556c76186b1fc943c7d8d460712d58f (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-118766; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-118766; retrieved 2026-11-04; source updated Not reported

Revision: 23ede8c008156ce35c028671c2e08bdc8772e94e37f4ae80213cd1cbd2a0ed66

Canonical: https://y2.dev/cve/CVE-2026-118766

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