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CVE-2024-53863

HIGHCVSS 8.2/10EPSS 0.61%

Last modified

CVE-2024-53863 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. Synapse is an open-source Matrix homeserver. In Synapse versions before 1.120.1, enabling the dynamic_thumbnails option or processing a specially crafted request could trigger the decoding and thumbnail generation of uncommon image formats, potentially invoking external tools like Ghostscript for processing. EPSS estimates a 0.61% chance of exploitation in the next 30 days.

Description

Synapse is an open-source Matrix homeserver. In Synapse versions before 1.120.1, enabling the dynamic_thumbnails option or processing a specially crafted request could trigger the decoding and thumbnail generation of uncommon image formats, potentially invoking external tools like Ghostscript for processing. This significantly expands the attack surface in a historically vulnerable area, presenting a risk that far outweighs the benefit, particularly since these formats are rarely used on the open web or within the Matrix ecosystem. Synapse 1.120.1 addresses the issue by restricting thumbnail generation to images in the following widely used formats: PNG, JPEG, GIF, and WebP. This vulnerability is fixed in 1.120.1.

Metrics

CVSS 3.1
9.1/10

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

CVSS 4.0
8.2/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.61%

44.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
MatrixSynapse< 1.120.1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2024-53863?
Synapse is an open-source Matrix homeserver. In Synapse versions before 1.120.1, enabling the dynamic_thumbnails option or processing a specially crafted request could trigger the decoding and thumbnail generation of uncommon image formats, potentially invoking external tools like Ghostscript for processing. This significantly expands the attack surface in a historically vulnerable area, presenting a risk that far outweighs the benefit, particularly since these formats are rarely used on the open web or within the Matrix ecosystem. Synapse 1.120.1 addresses the issue by restricting thumbnail generation to images in the following widely used formats: PNG, JPEG, GIF, and WebP. This vulnerability is fixed in 1.120.1.
How severe is CVE-2024-53863?
CVE-2024-53863 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.61% probability of exploitation in the next 30 days.
How do I fix CVE-2024-53863?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2024-53863?

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Source: NVD / NIST