CVE-2024-56515: matrix-media-repo — Fix

Description

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. If SVG or JPEGXL thumbnailers are enabled (they are disabled by default), a user may upload a file which claims to be either of these types and request a thumbnail to invoke a different decoder in ImageMagick. In some ImageMagick installations, this includes the capability to run Ghostscript to decode the image/file. If MP4 thumbnailers are enabled (also disabled by default), the same issue as above may occur with the ffmpeg installation instead. MMR uses a number of other decoders for all other file types when preparing thumbnails. Theoretical issues are possible with these decoders, however in testing they were not possible to exploit. This is fixed in MMR v1.3.8. MMR now inspects the mimetype of media prior to thumbnailing, and picks a thumbnailer based on those results instead of relying on user-supplied values. This may lead to fewer thumbnails when obscure file shapes are used. This also helps narrow scope of theoretical issues with all decoders MMR uses for thumbnails. Users are advised to upgrade. Users unable to upgrade may disable the SVG, JPEGXL, and MP4 thumbnail types in the MMR config which prevents the decoders from being invoked. Further disabling uncommon file types on the server is recommended to limit risk surface. Containers and other similar technologies may also be used to limit the impact of vulnerabilities in external decoders, like ImageMagick and ffmpeg. Some installations of ImageMagick may disable "unsafe" file types, like PDFs, already. This option can be replicated to other environments as needed. ffmpeg may be compiled with limited decoders/codecs. The Docker image for MMR disables PDFs and similar formats by default.

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CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Affected Products

Vendor	Product	Versions
t2bot	matrix-media-repo	< 1.3.8

References

Advisories & Patches

https://github.com/t2bot/matrix-media-repo/security/advisories/GHSA-rcxc-wjgw-579r

Other References

https://github.com/t2bot/matrix-media-repo/releases/tag/v1.3.8

Frequently Asked Questions

What is CVE-2024-56515? +

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. If SVG or JPEGXL thumbnailers are enabled (they are disabled by default), a user may upload a file which claims to be either of these types and request a thumbnail to invoke a different decoder in ImageMagick. In some ImageMagick installations, this includes the capability to run Ghostscript to decode the image/file. If MP4 thumbnailers are enabled (also disabled by default), the same issue as above may occur with the ffmpeg installation instead. MMR uses a number of other decoders for all other file types when preparing thumbnails. Theoretical issues are possible with these decoders, however in testing they were not possible to exploit. This is fixed in MMR v1.3.8. MMR now inspects the mimetype of media prior to thumbnailing, and picks a thumbnailer based on those results instead of relying on user-supplied values. This may lead to fewer thumbnails when obscure file shapes are used. This also helps narrow scope of theoretical issues with all decoders MMR uses for thumbnails. Users are advised to upgrade. Users unable to upgrade may disable the SVG, JPEGXL, and MP4 thumbnail types in the MMR config which prevents the decoders from being invoked. Further disabling uncommon file types on the server is recommended to limit risk surface. Containers and other similar technologies may also be used to limit the impact of vulnerabilities in external decoders, like ImageMagick and ffmpeg. Some installations of ImageMagick may disable "unsafe" file types, like PDFs, already. This option can be replicated to other environments as needed. ffmpeg may be compiled with limited decoders/codecs. The Docker image for MMR disables PDFs and similar formats by default. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2024-56515? +

CVE-2024-56515 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-56515? +

CVE-2024-56515 affects products from t2bot, specifically: matrix-media-repo. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-56515? +

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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