CVE-2026-35544
Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages
CVE-2026-35544 is a medium vulnerability (CVSS 5.3) in Bulwarkmail Webmail, published April 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. Fixed in roundcube/roundcubemail 1.7-rc5.
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2026-35544- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-669
- Updated
- 2026-11-02
EUVDEUVD-2026-18591
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.
- Record
EUVD-2026-18591- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xpqh-grpw-4xmg
Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages
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.
- Record
GHSA-xpqh-grpw-4xmg- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-669
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-35544- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-669
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2026-35544- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-669
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-35544
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.
- Record
DEBIAN-CVE-2026-35544- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-xpqh-grpw-4xmg
Roundcube Webmail: Insufficient CSS sanitization in HTML e-mail messages
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.
- Record
GHSA-xpqh-grpw-4xmg- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-669
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-35544
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.
- Record
UBUNTU-CVE-2026-35544- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
roundcube/roundcubemailPackagist |
1.7-beta up to 1.7-rc5 | 1.7-rc5 |
roundcubeDebian:12 |
before 1.6.5+dfsg-1+deb12u8, plus listed versions 1.6.1+dfsg-11.6.2+dfsg-11.6.3+dfsg-11.6.3+dfsg-1~deb12u11.6.3+dfsg-2 Show 10 moreShow less1.6.4+dfsg-11.6.4+dfsg-1~deb12u11.6.5+dfsg-11.6.5+dfsg-1+deb12u21.6.5+dfsg-1+deb12u31.6.5+dfsg-1+deb12u41.6.5+dfsg-1+deb12u51.6.5+dfsg-1+deb12u61.6.5+dfsg-1+deb12u71.6.5+dfsg-1~deb12u1 |
1.6.5+dfsg-1+deb12u8 |
roundcubeDebian:13 |
before 1.6.15+dfsg-0+deb13u1, plus listed versions 1.6.11+dfsg-11.6.12+dfsg-0+deb13u11.6.12+dfsg-11.6.13+dfsg-0+deb13u11.6.13+dfsg-11.6.14+dfsg-1 |
1.6.15+dfsg-0+deb13u1 |
roundcubeDebian:14 |
before 1.6.14+dfsg-1, plus listed versions 1.6.11+dfsg-11.6.12+dfsg-11.6.13+dfsg-1 |
1.6.14+dfsg-1 |
roundcube/roundcubemailPackagist |
1.7-beta up to 1.7-rc5, plus listed versions 1.7-beta21.7-rc1.7-rc21.7-rc31.7-rc4 |
1.7-rc5 |
roundcubeUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 1.1.1+dfsg.1-21.1.2+dfsg.1-51.1.3+dfsg.1-11.1.4+dfsg.1-11.2~beta+dfsg.1-0ubuntu1 Show 8 moreShow less1.2~beta+dfsg.1-0ubuntu1+esm11.2~beta+dfsg.1-0ubuntu1+esm21.2~beta+dfsg.1-0ubuntu1+esm31.2~beta+dfsg.1-0ubuntu1+esm41.2~beta+dfsg.1-0ubuntu1+esm51.2~beta+dfsg.1-0ubuntu1+esm61.2~beta+dfsg.1-0ubuntu1+esm71.2~beta+dfsg.1-0ubuntu1+esm8 |
None known |
roundcubeUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 1.3.0+dfsg.1-11.3.1+dfsg.1-11.3.3+dfsg.1-11.3.3+dfsg.1-21.3.6+dfsg.1-1 Show 8 moreShow less1.3.6+dfsg.1-1ubuntu0.1~esm11.3.6+dfsg.1-1ubuntu0.1~esm21.3.6+dfsg.1-1ubuntu0.1~esm31.3.6+dfsg.1-1ubuntu0.1~esm41.3.6+dfsg.1-1ubuntu0.1~esm51.3.6+dfsg.1-1ubuntu0.1~esm61.3.6+dfsg.1-1ubuntu0.1~esm71.3.6+dfsg.1-1ubuntu0.1~esm8 |
None known |
roundcubeUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 1.3.8+dfsg.1-21.3.10+dfsg.1-11.4.1+dfsg.1-21.4.2+dfsg.1-11.4.2+dfsg.1-2 Show 9 moreShow less1.4.3+dfsg.1-11.4.3+dfsg.1-1ubuntu0.1~esm11.4.3+dfsg.1-1ubuntu0.1~esm21.4.3+dfsg.1-1ubuntu0.1~esm31.4.3+dfsg.1-1ubuntu0.1~esm41.4.3+dfsg.1-1ubuntu0.1~esm51.4.3+dfsg.1-1ubuntu0.1~esm61.4.3+dfsg.1-1ubuntu0.1~esm71.4.3+dfsg.1-1ubuntu0.1~esm8 |
None known |
roundcubeUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 1.4.11+dfsg.1-41.5.0+dfsg.1-21.5.0+dfsg.1-2ubuntu0.1~esm11.5.0+dfsg.1-2ubuntu0.1~esm21.5.0+dfsg.1-2ubuntu0.1~esm31.5.0+dfsg.1-2ubuntu0.1~esm41.5.0+dfsg.1-2ubuntu0.1~esm51.5.0+dfsg.1-2ubuntu0.1~esm6 |
None known |
roundcubeUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 1.6.2+dfsg-11.6.4+dfsg-11.6.5+dfsg-11.6.6+dfsg-11.6.6+dfsg-2 Show 4 moreShow less1.6.6+dfsg-2ubuntu0.11.6.6+dfsg-2ubuntu0.1+esm11.6.6+dfsg-2ubuntu0.1+esm21.6.6+dfsg-2ubuntu0.1+esm3 |
None known |
roundcubeUbuntu:25.10 |
All versions, plus listed versions 1.6.10+dfsg-11.6.10+dfsg-21.6.11+dfsg-1 |
None known |
roundcubeUbuntu:26.10 |
All versions, plus listed versions 1.6.11+dfsg-1 |
None known |
roundcubeUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 1.6.11+dfsg-11.6.11+dfsg-1ubuntu0.26.04.1~esm1 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14
github.com/roundcube/roundcubemail/releases/tag/1.7-rc5
Show 9 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-35544
security-tracker.debian.org/tracker/CVE-2026-35544
ubuntu.com/security/CVE-2026-35544
cve.org/CVERecord?id=CVE-2026-35544
nullcathedral.com/posts/2026-03-18-roundcube-round-two-three-more-sanitizer-bypasses