# CVE-2026-40019: dovecot: An unauthenticated attacker can send a truncated quoted argument to the ManageSieve login process, which makes it spi...

CVE-2026-40019 is fixed in 11 products on 1 platform, first by RHSA-2026:79371, released August 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-40019
- Priority: High
- CVSS: 9.1 (important)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 28, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dovecot Debian 14 | 1:2.4.5+dfsg1-1 | [DEBIAN-CVE-2026-40019](https://patchblox.com/security/data/fix/linux/debian-cve-2026-40019.md) | Sep 10, 2026 |
| Linux | dovecot Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot RHEL 10 | 2.3.21-19.el10_2.8 | [RHSA-2026:79371](https://patchblox.com/security/data/fix/linux/rhsa-2026-79371.md) | Aug 28, 2026 |
| Linux | dovecot RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot rocky 10 | 1:2.3.21-19.el10_2.8 | [RLSA-2026:79371](https://patchblox.com/security/data/fix/linux/rlsa-2026-79371.md) | Nov 7, 2026 |
| Linux | dovecot rocky 8 | 1:2.3.16-16.el8_10 | [RLSA-2026:76763](https://patchblox.com/security/data/fix/linux/rlsa-2026-76763.md) | Oct 7, 2026 |
| Linux | dovecot rocky 9 | 1:2.3.16-18.el9_8.8 | [RLSA-2026:80825](https://patchblox.com/security/data/fix/linux/rlsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-debugsource Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-devel Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-devel RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-devel almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-devel almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-devel ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-devel ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-mysql RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-mysql almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-mysql almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-mysql ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pgsql Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pgsql RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-pgsql almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pgsql almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pgsql ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pgsql ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pgsql-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pigeonhole Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pigeonhole RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-pigeonhole almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pigeonhole almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pigeonhole ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pigeonhole ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pigeonhole-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot23 sles 15.6 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 |
| Linux | dovecot23 sles 15.7 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 |

---

Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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