Description
Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by an IMAP command injection vulnerability. A remote authenticated attacker can exploit this via CRLF sequences injected into the _flag parameter of the mail/mark action to execute arbitrary IMAP commands. Upstream fixed this in the commit “Fix IMAP command injection via CRLF in `_flag` parameter of mail/mark action”, which rejects flags containing control, whitespace and IMAP-special characters.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Roundcube | Webmail | 1.6.0 – < 1.6.20, 1.7.0 – < 1.7.5 | 1.6.20 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | roundcube | 1.6.20+dfsg-1 | — |
| Debian 13 | roundcube | 1.6.20+dfsg-0+deb13u1 | — |
| Debian 12 | roundcube | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | roundcube | No fix yet | — |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | roundcube | No fix yet | — |
| Ubuntu Pro 24.04 LTS | roundcube | No fix yet | — |
| Ubuntu Pro 22.04 LTS | roundcube | No fix yet | — |
| Ubuntu Pro 20.04 LTS | roundcube | No fix yet | — |
| Ubuntu Pro 18.04 LTS | roundcube | No fix yet | — |
| Ubuntu Pro 16.04 LTS | roundcube | No fix yet | — |
Advisories 1
- WID-SEC-2026-4043 Roundcube Webmail: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 5, 2026
References
- https://bugs.debian.org/1151279 issue-tracking third-party-advisory
- https://github.com/roundcube/roundcubemail/commit/6c3c1897c11e193e47fccaabc87e9ca2a0a73e51 patch
- https://roundcube.net/news/2026/10/19/security-updates-1.6.20-and-1.7.5 vendor-advisory release-notes
- https://github.com/roundcube/roundcubemail/releases/tag/1.7.5 release-notes patch
- https://github.com/roundcube/roundcubemail/releases/tag/1.6.20 release-notes patch
- https://github.com/roundcube/roundcubemail/commit/242c6d6a150c850bd96d20d400261e71f8d11f9b patch