What is CVE-2024-52815?

CVE-2024-52815 is a medium-severity vulnerability in Element-Hq Synapse, classified under Improper Input Validation. CVSS score: 5.3/10. Published 2024-12-03.

How severe is CVE-2024-52815?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Improper input validation in Element-Hq Synapse

CVE-2024-52815

Synapse is an open-source Matrix homeserver. Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's /sync functionality. Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2024-12-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.006 (45.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.000

Affected products

Element-Hq Synapse — versions < 1.120.1
Matrix Synapse

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

github.com/element-hq/synapse/security/advisories/GHSA-f3r3-h2mq-hx2h (Vendor Advisory)

Frequently asked questions

What is CVE-2024-52815?: CVE-2024-52815 is a medium-severity vulnerability in Element-Hq Synapse, classified under Improper Input Validation. CVSS score: 5.3/10. Published 2024-12-03.
How severe is CVE-2024-52815?: Medium severity. CVSS v3 base score is 5.3 out of 10.