| Name | CVE-2026-40019 |
| Description | An unauthenticated attacker can send a truncated quoted argument to the ManageSieve login process, which makes it spin in an infinite loop consuming CPU. This can cause degradation or denial of service for Sieve script management, and repeated connections can consume all available CPU on the server. Monitor system for abnormal CPU usage and kill the offending process. Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1146018 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| dovecot (PTS) | bookworm, bookworm (security) | 1:2.3.19.1+dfsg1-2.1+deb12u6 | fixed |
| trixie | 1:2.4.1+dfsg1-6+deb13u6 | fixed |
| trixie (security) | 1:2.4.1+dfsg1-6+deb13u7 | fixed |
| forky | 1:2.4.5+dfsg1-2 | fixed |
| sid | 1:2.4.5+dfsg1-3 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| dovecot | source | bookworm | (not affected) | | | |
| dovecot | source | trixie | (not affected) | | | |
| dovecot | source | (unstable) | 1:2.4.5+dfsg1-1 | | | 1146018 |
Notes
[trixie] - dovecot <not-affected> (Vulnerable code not present, introduced in 2.4.3)
[bookworm] - dovecot <not-affected> (Vulnerable code not present, introduced in 2.4.3)
https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html#cve-2026-40019-v2-4-3-regression-managesieve-login-pre-auth-infinite-loop