CVE-2024-53863

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.

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CVSS v3.1 Score

9.1

CRITICAL

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

Weakness Type (CWE)

CWE-434 Unrestricted Upload

Affected Products

Vendor	Product	Versions
matrix	synapse	< 1.120.1

References

Advisories & Patches

https://github.com/element-hq/synapse/security/advisories/GHSA-vp6v-whfm-rv3g

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2024-53863? +

CVE-2024-53863 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2024-53863? +

CVE-2024-53863 affects products from matrix, specifically: synapse. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-53863? +

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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