9.1

CVE-2024-53863: element-hq synapse

CVSS: 9.1v3.1CriticalAnalyzed
AliasesGHSA-vp6v-whfm-rv3gPYSEC-2026-1615UBUNTU-CVE-2024-53863
Published 03-12-2024Last modified 03-12-2024
Open JSON

Vulnerability summary

CVE-2024-53863 is a critical (CVSS 9.1) vulnerability in element-hq synapse. EPSS estimates a 0.61% chance of exploitation in the next 30 days, higher than 48% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (NVD)
EPSS score
0.61%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2024:14541-1USN-7444-1

Timeline

  1. 03-12-2024
    PublishedVulnerability first disclosed.
  2. 03-12-2024
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.61%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

0.00 pp

From 0.61% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.61%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • matrix-synapse< 1.121.0-1
Element-hq1 product
Matrix1 product
PyPI1 product
  • matrix-synapse< 1.120.1
Ubuntu1 product
  • matrix-synapse< 1.53.0-1ubuntu0.1~esm2 | All versions (No fix recorded)

5 vendors · 5 products

References

10 links