CVE-2026-40020

NameCVE-2026-40020
DescriptionAttacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_allow_anyone=no. This causes folders to be spammed to all users. The impact is limited to being able to spam folders to other users, no unexpected access is gained. Install to fixed version. No publicly available exploits are known.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6313-1
Debian Bugs1136444

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
dovecot (PTS)bullseye1:2.3.13+dfsg1-2+deb11u1vulnerable
bullseye (security)1:2.3.13+dfsg1-2+deb11u3vulnerable
bookworm1:2.3.19.1+dfsg1-2.1+deb12u5vulnerable
bookworm (security)1:2.3.19.1+dfsg1-2.1+deb12u6fixed
trixie1:2.4.1+dfsg1-6+deb13u5vulnerable
trixie (security)1:2.4.1+dfsg1-6+deb13u6fixed
forky, sid1:2.4.4+dfsg1-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
dovecotsourcebookworm1:2.3.19.1+dfsg1-2.1+deb12u6DSA-6313-1
dovecotsourcetrixie1:2.4.1+dfsg1-6+deb13u6DSA-6313-1
dovecotsource(unstable)1:2.4.4+dfsg1-11136444

Notes

https://www.openwall.com/lists/oss-security/2026/05/12/6
Fixed by: https://github.com/dovecot/core/commit/b7daa4104ff064c1fb549540cc9d96c2d9e2509c (2.4.4)
Fixed by: https://github.com/dovecot/core/commit/20b48c3db5fed7ccaa8e0a4c10ca54f6dc36a63d (2.4.4)
Fixed by: https://github.com/dovecot/core/commit/1cf6ad1a119e5dace816e401e73ba6cc11d1472e (2.4.4)

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