Description
Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a mail header injection vulnerability. rcmail_sendmail stripped newline characters only from the Subject and Organization headers, leaving other header values taken from request parameters unsanitized, so a remote authenticated attacker could inject arbitrary headers into an outgoing message via the References, In-Reply-To, Message-ID and From parameters. Upstream fixed this in the commit “Fix mail header injection via References/In-Reply-To/Message-ID/From parameters”, which normalizes whitespace in every string header value.
Affected products
roundcube: webmail
References6
- github.com/roundcube/roundcubemail/commit/79adcfc0c48012bbbe930… PatchMailing List
- github.com/roundcube/roundcubemail/commit/acd32a86f631dd6dcda8a… Patch
- bugs.debian.org/1151279 Third Party Advisory
- github.com/roundcube/roundcubemail/releases/tag/1.6.20 Release Notes
- github.com/roundcube/roundcubemail/releases/tag/1.7.5 Release Notes
- roundcube.net/news/2026/10/19/security-updates-1.6.20-and-1.7.5 Issue Tracking
Metrics
- CVSS 3.1
-
5.0
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 26 · as of 8 November 2026
- CWE
- CWE-99
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.