What is CVE-2026-45076?

CVE-2026-45076 is a low-severity vulnerability in Element Synapse, classified under Improper Input Validation. CVSS score: 2.7/10. Published 2026-05-28.

How severe is CVE-2026-45076?

Low severity. CVSS v3 base score is 2.7 out of 10.

Improper input validation in Element Synapse

CVE-2026-45076

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients co…

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

EPSS: 0.001 (25.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L.

Affected products

Element Synapse
Element-hq Synapse — versions < 1.152.1

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-45076?: CVE-2026-45076 is a low-severity vulnerability in Element Synapse, classified under Improper Input Validation. CVSS score: 2.7/10. Published 2026-05-28.
How severe is CVE-2026-45076?: Low severity. CVSS v3 base score is 2.7 out of 10.