CVE-2024-53863 - CVE House
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Status published High CVE-2024-53863

Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

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Affected Vendor

Affected Software

synapse
Vulnerable Versions:
< 1.120.1

Timeline

Official Publish: December 3rd, 2024
Last Modified: December 3rd, 2024
Added to House: July 22nd, 2026

CVSS Vectors

Weaknesses (CWE)

CWE-434

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1505.003 Web Shell
Persistence
T1105 Ingress Tool Transfer
Command and Control
T1059 Command and Scripting Interpreter
Execution
T1565.002 Stored Data Manipulation
Impact