CVE-2026-78433: Access Control Flaw

Description

Gitea's web attachment handler skips its cross-repository ownership check for attachments created before 16 January 2026 and checks permissions against the repository named in the request URL instead. An unauthenticated attacker who knows a private attachment's UUID can request it through a public repository's attachment path and retrieve its contents. This can expose issue and pull request attachments or release assets; the random attachment UUID must already be known to the attacker.

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Weakness Type (CWE)

CWE-284 CWE-284

CWE-639 CWE-639

CWE-863 Incorrect Authorization

CWE-1220 CWE-1220

References

Other References

https://blog.gitea.com/release-of-1.27.3/ https://github.com/go-gitea/gitea/pull/39048 https://github.com/go-gitea/gitea/pull/39077 https://github.com/go-gitea/gitea/releases/tag/v1.27.3 https://github.com/go-gitea/gitea/security/advisories/GHSA-frpv-2xgv-wxpq

Frequently Asked Questions

What is CVE-2026-78433? +

Gitea's web attachment handler skips its cross-repository ownership check for attachments created before 16 January 2026 and checks permissions against the repository named in the request URL instead. An unauthenticated attacker who knows a private attachment's UUID can request it through a public repository's attachment path and retrieve its contents. This can expose issue and pull request attachments or release assets; the random attachment UUID must already be known to the attacker.

How do I check if I'm vulnerable to CVE-2026-78433? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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