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

> Attackers can bypass client certificate authentication in Sunshine to access protected endpoints due to improper OpenSSL verification handling.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 May 2026
- **Updated:** 26 May 2026
- **Also known as:** GHSA-ph75-mgxh-mv57

## What is CVE-2026-32253?

CVE-2026-32253 is a critical authentication bypass vulnerability in LizardByte Sunshine, published on 22 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-295 (Improper Certificate Validation), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-32253?

It affects 1 product.


Products: Lizardbyte Sunshine.

## How do I fix CVE-2026-32253?

No fix has been published for CVE-2026-32253 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-32253 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32253 exists.

## Other vulnerabilities in LizardByte Sunshine

- [CVE-2025-53095](https://insights.sbomify.com/CVE-2025-53095/): Sunshine application-wide CSRF in the UI leads to command injection as Administrator (critical 9.7)
- [CVE-2025-10198](https://insights.sbomify.com/CVE-2025-10198/): LizardBytes Sunshine for Windows contains a DLL search-order hijacking vulnerability (high 7.8)
- [CVE-2025-10199](https://insights.sbomify.com/CVE-2025-10199/): A local privilege escalation vulnerability exists in LizardBytes' Sunshine for Windows (high 7.8)
- [CVE-2024-51738](https://insights.sbomify.com/CVE-2024-51738/): Sunshine improperly enforces pairing protocol request order (high 7.7)
- [CVE-2024-31220](https://insights.sbomify.com/CVE-2024-31220/): Sunshine vulnerable to remote unauthenticated arbitrary file read (high 7.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-32253 and fix it if it is affected.

What it is: CVE-2026-32253 is a critical authentication bypass vulnerability in LizardByte Sunshine, published on 22 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32253 exists.

Affected product: LizardByte Sunshine. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-32253/ (Markdown: https://insights.sbomify.com/CVE-2026-32253/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32253
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32253
- OSV: https://osv.dev/vulnerability/CVE-2026-32253

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-32253/
Summaries are generated and may contain mistakes; the official description above is the record.