5.4

CVE-2026-74999: roundcube webmail Cross-site Scripting

CVSS: 5.4v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-74999DEBIAN-CVE-2026-74999
Published 17-08-2026Last modified 17-08-2026
Open JSON

Vulnerability summary

CVE-2026-74999 is a medium (CVSS 5.4) Cross-site Scripting vulnerability in roundcube webmail. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 21.8% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.30%
0%100%
Low · +0.09 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 1
OPENSUSE-SU-2026:12169-1

Timeline

  1. 17-08-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, the "Add to address book" action was subject to stored XSS.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.30%

Chance of exploitation in the next 30 days

Percentile

22%

Versus all other CVEs

30-day change

+0.09 pp

From 0.22% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.30%

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

Debian1 product
  • roundcube< 1.6.5+dfsg-1+deb12u11 | < 1.6.18+dfsg-0+deb13u1 | < 1.6.18+dfsg-1
Roundcube1 product
  • webmail≥ 1.6.0, < 1.6.18 | ≥ 1.7.0, < 1.7.3
Ubuntu1 product
  • roundcubeAll versions (No fix recorded)

3 vendors · 3 products

References

8 links