CVE-2024-56515

CVE-2024-56515 is a medium-severity vulnerability in T2bot Matrix-media-repo with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

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.

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.
How severe is CVE-2024-56515?
CVE-2024-56515 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2024-56515 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-56515?
CVE-2024-56515 affects T2bot Matrix-media-repo. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-56515?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-56515 have an EU (EUVD) identifier?
Yes. CVE-2024-56515 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-0104.
When was CVE-2024-56515 published?
CVE-2024-56515 was published on 2025-01-16 and last updated on 2026-06-17.

References

Affected products (1)

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