6.8

CVE-2026-45078: element-hq synapse

CVSS: 6.8v4.0MediumAnalyzed
AliasesGHSA-8q93-326v-3m7gPYSEC-2026-191UBUNTU-CVE-2026-45078
Published 28-05-2026Last modified 29-05-2026
Open JSON

Vulnerability summary

CVE-2026-45078 is a medium (CVSS 6.8) vulnerability in element-hq synapse. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.5% of scored vulnerabilities.

Overall risk
27/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.8/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.13%
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 1 · Related 2
OPENSUSE-SU-2026:10898-1CGA-H5HG-HJ67-9GWX

Timeline

  1. 28-05-2026
    PublishedVulnerability first disclosed.
  2. 29-05-2026
    Last modifiedVulnerability information updated.

Description

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1.

CVSS metrics

8 scores · 6 sources · 2 versions

EPSS trend

Probability

0.13%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

0.00 pp

From 0.13% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.13%

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

Chainguard1 product
  • synapse< 1.153.0-r0
Debian1 product
  • matrix-synapse< 1.152.1-1
Element1 product
Element-hq1 product
PyPI1 product
  • matrix-synapse< 1.152.1
Ubuntu1 product
  • matrix-synapseAll versions (No fix recorded)

6 vendors · 6 products

References

10 links