CVE-2026-35544: roundcube webmail
CVSS: 5.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-35544DEBIAN-CVE-2026-35544
Published 03-04-2026Last modified 03-04-2026
Vulnerability summary
CVE-2026-35544 is a medium (CVSS 5.3) vulnerability in roundcube webmail. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 42.3% of scored vulnerabilities.
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)EPSS score
0.51%
0%100%
Low · +0.14 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 03-04-2026PublishedVulnerability first disclosed.
- 03-04-2026Last modifiedVulnerability information updated.
Description
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
CVSS metrics
4 scores · 4 sources · 1 versionMedium 5.3Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NSourcesAll 4 agree
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
0.51%
Chance of exploitation in the next 30 days
Percentile
42%
Versus all other CVEs
30-day change
+0.14 pp
From 0.37% on 21-09-2026
21-09-202621-10-2026
EPSS score0.51%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- roundcube< 1.6.5+dfsg-1+deb12u8 | < 1.6.15+dfsg-0+deb13u1 | < 1.6.14+dfsg-1
Roundcube1 product
- webmail< 1.5.14 | ≥ 1.6.0, < 1.6.14 | ≤ 1.5.13 | ≥ 1.6.0, ≤ 1.6.13
Ubuntu1 product
- roundcubeAll versions (No fix recorded)
3 vendors · 3 products
