CVE-2026-20736

High

Published: 22 January 2026

Published

22 January 2026

Modified

29 January 2026

KEV Added

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Patch

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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Score 0.0002 4.6th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-20736 is a high-severity Improper Access Control (CWE-284) vulnerability in Gitea Gitea. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Stored Data Manipulation (T1565.001); ranked at the 4.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-6 (Least Privilege).

Deeper analysis

CVE-2026-20736 affects Gitea, an open-source self-hosted Git service, due to improper verification of repository context during attachment deletion. Specifically, the vulnerability allows a user who previously uploaded an attachment to a repository to delete it even after losing access to that repository. Published on 2026-01-22, it carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and maps to CWE-284 (Improper Access Control).

Any authenticated user with access to at least one repository can exploit this by crafting a delete request for an attachment from a different repository they previously had write access to but no longer do. Successful exploitation results in unauthorized deletion of attachments, enabling integrity violations such as removal of critical files or evidence without the owner's consent.

Gitea's security advisory (GHSA-jr6h-pwwp-c8g6) and release notes for version 1.25.4 confirm the issue was addressed in pull request #36320. Administrators should update to Gitea 1.25.4 or later to mitigate the vulnerability, as no workarounds are specified in the provided references.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-4269

Vulnerability details

Gitea does not properly verify repository context when deleting attachments. A user who previously uploaded an attachment to a repository may be able to delete it after losing access to that repository by making the request through a different repository…

they can access.

CWE(s): CWE-284

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1565.001 Stored Data Manipulation Impact

Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.

attack.mitre.org →

T1070.004 File Deletion Stealth

Adversaries may delete files left behind by the actions of their intrusion activity.

attack.mitre.org →

Why these techniques?

Improper access control enables unauthorized deletion of stored repository attachments (Stored Data Manipulation) and supports removal of files/evidence (File Deletion).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1