9

CVE-2026-40541: synology synology chat server Cross-site Scripting

CVSS: 9.0v3.1CriticalUndergoing analysis
Published 28-08-2026Last modified 28-08-2026
Open JSON

Vulnerability summary

CVE-2026-40541 is a critical (CVSS 9.0) Cross-site Scripting vulnerability in synology synology chat server. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 41% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.0/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.49%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 28-08-2026
    PublishedVulnerability first disclosed.
  2. 28-08-2026
    Last modifiedVulnerability information updated.

Description

An improper neutralization of input during web page generation ('Cross-site Scripting') vulnerability in extract domain in Synology Chat Server before 2.4.5-22148 allows remote authenticated users, via a UI interaction, to read or write arbitrary files and conduct denial-of-service attacks in DSM.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.49%

Chance of exploitation in the next 30 days

Percentile

41%

Versus all other CVEs

30-day change

+0.01 pp

From 0.48% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.49%

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

Synology1 product

1 vendor · 1 product

References

1 links