What’s Vulnerable › Vulnerabilities

CVE-2021-29453: Denial of service through memory exhaustion

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-19 · updated 2026-06-17
• Weakness: CWE-400

Description

matrix-media-repo is an open-source multi-domain media repository for Matrix. Versions 1.2.6 and earlier of matrix-media-repo do not properly handle malicious images which are crafted to be small in file size, but large in complexity. A malicious user could upload a relatively small image in terms of file size, using particular image formats, which expands to have extremely large dimensions during the process of thumbnailing. The server can be exhausted of memory in the process of trying to load the whole image into memory for thumbnailing, leading to denial of service. Version 1.2.7 has a fix for the vulnerability.

Affected products

• Matrix-Media-Repo Project Matrix-Media-Repo: before 1.2.7 — fixed in 1.2.7

How to fix

Upgrade to a fixed version: Matrix-Media-Repo Project Matrix-Media-Repo 1.2.7. Check the vendor advisory for mitigations.

References

• https://github.com/turt2live/matrix-media-repo/releases/tag/v1.2.7
• https://github.com/turt2live/matrix-media-repo/security/advisories/GHSA-j889-h476-hh9h
• https://hub.docker.com/r/turt2live/matrix-media-repo/tags?page=1&ordering=last_updated
• https://github.com/turt2live/matrix-media-repo/releases/tag/v1.2.7
• https://github.com/turt2live/matrix-media-repo/security/advisories/GHSA-j889-h476-hh9h
• https://hub.docker.com/r/turt2live/matrix-media-repo/tags?page=1&ordering=last_updated

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