CVE-2024-53863
moderate-risk
Published 2024-12-03
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.
Do I need to act?
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0.71% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
9
CVSS 9.1/10
Critical
NETWORK
/ LOW complexity
Affected Products (1)
Affected Vendors
References (1)
38
/ 100
moderate-risk
Severity
31/34 · Critical
Exploitability
2/34 · Minimal
Exposure
5/34 · Minimal