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Mallory
Medium

Attachment Extension Bypass in Gitea <1.23.0 via Attachment API

IdentifiersCVE-2025-68939CWE-424· Improper Protection of Alternate…

CVE-2025-68939 is a vulnerability in Gitea versions prior to 1.23.0 that allows attackers to bypass file extension restrictions on attachments. By editing the attachment name through the attachment API, an attacker can upload files with forbidden extensions, such as executable or script files, which are normally blocked. This is due to improper protection of alternate paths in the attachment handling logic, specifically failing to enforce extension restrictions after renaming via the API.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows attackers to upload and distribute files with forbidden extensions, potentially leading to the execution of malicious code, distribution of malware, or other security risks associated with the handling of dangerous file types. The vulnerability is remotely exploitable and increases the risk of compromise, especially if users interact with the malicious attachments.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, restrict access to the attachment API, monitor for suspicious attachment uploads, and implement additional file validation on the server side to block forbidden extensions regardless of filename changes.

Remediation

Patch, then assume compromise.

Upgrade Gitea to version 1.23.0 or later, where the vulnerability has been addressed. The patch ensures that file extension restrictions are properly enforced even after attachment names are edited via the API.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
GiteaGiteaapplication

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What this page doesn’t show

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

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Social activity5

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