Vulnerability · Published Dec 3, 2024 · Assigned by GitHub_M
CVE-2024-53863Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders
High 8.2
In plain English
A high-severity unrestricted file upload in synapse from element-hq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | synapse | 1.120.1 | ALPINE-CVE-2024-53863 |
| Alpine:v3.21 | synapse | 1.120.2-r0 | ALPINE-CVE-2024-53863 |
| Alpine:v3.22 | synapse | 1.120.2-r0 | ALPINE-CVE-2024-53863 |
| Alpine:v3.23 | synapse | 1.120.2-r0 | ALPINE-CVE-2024-53863 |
| Alpine:v3.24 | synapse | 1.120.2-r0 | ALPINE-CVE-2024-53863 |
| Debian:14 | matrix-synapse | 1.121.0-1 | DEBIAN-CVE-2024-53863 |
| PyPI | matrix-synapse | 1.120.1 | GHSA-vp6v-whfm-rv3g |
| PyPI | matrix-synapse | 1.120.1 | PYSEC-2026-1615 |
| Ubuntu:24.04:LTS | matrix-synapse | no fix listed | UBUNTU-CVE-2024-53863 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| element-hq | synapse | < 1.120.1 |
Weakness: CWE-434 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/element-hq/synapse/security/advisories/GHSA-vp6v-whfm-rv3g x_refsource_CONFIRM