TI-2024-36056 Aliases CVE-2024-53863 GHSA-vp6v-whfm-rv3g

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

MEDIUM 43CWE-434Published 2024-12-03 · Updated 2024-12-03

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: Code execution
Confidentiality · integrity · availability: None · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-434.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00606 49th percentileScored 2026-11-07

Fix Fixed synapse (element-hq): 1.120.1matrix-synapse (PyPI): 1.120.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
element-hq	synapse	before 1.120.1	1.120.1	Patch available	CNA
—	matrix-synapse (PyPI)	before 1.120.1	1.120.1	Patch available	GHSA-vp6v-whfm-rv3g

synapse Vendorelement-hq Affected before 1.120.1 Fixed in 1.120.1 Patch available CNA
matrix-synapse (PyPI) Vendor— Affected before 1.120.1 Fixed in 1.120.1 Patch available GHSA-vp6v-whfm-rv3g

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:matrix:synapse::::::::	before 1.120.1	Vulnerable	matrix-org

cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* Versions before 1.120.1 Vulnerable ·matrix-org

Remediation

Fix · CNA synapse (element-hq) Fixed in 1.120.1
Fix · GHSA-vp6v-whfm-rv3g matrix-synapse (PyPI) Fixed in 1.120.1 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2024-53863
2026-10-03 Alias added: GHSA-vp6v-whfm-rv3g

References

Advisory 2

Other 1

https://github.com/element-hq/synapse

TI-2024-35327 Synapse allows a a malformed invite to break the invitee's `/sync` CVSS 4.0HIGH 8.7
TI-2024-35318 Synapse allows unsupported content types to lead to memory exhaustion CVSS 4.0HIGH 8.2
TI-2022-07650 Remote program execution with user interaction CVSS 3.1HIGH 8.8
TI-2026-19372 ESS Community Helm Chart has a weak server key generation method CVSS 4.0CRITICAL 9.2
TI-2024-24814 Synapse denial of service through media disk space consumption CVSS 3.1HIGH 7.5
TI-2026-35452 Element Call reports full URLs of visited pages to analytics server CVSS 4.0HIGH 8.6

See all 31 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences