Description
In Dovecot before 2.3.11.3, sending a specially formatted NTLM request will crash the auth service because of an out-of-bounds read.
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 | dovecot | 1:2.3.11.3+dfsg1-1 | — |
| Debian 13 | dovecot | 1:2.3.11.3+dfsg1-1 | — |
| Debian 12 | dovecot | 1:2.3.11.3+dfsg1-1 | — |
| Debian 10 | dovecot | 1:2.3.4.1-5+deb10u3 | DSA-4745-1 |
| Debian 9 | dovecot | 1:2.2.27-3+deb9u6 | DLA-2328-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | dovecot | 1:2.3.7.2-1ubuntu3.2 | USN-4456-1 |
| Ubuntu 18.04 LTS | dovecot | 1:2.2.33.2-1ubuntu4.6 | USN-4456-1 |
| Ubuntu 16.04 LTS | dovecot | 1:2.2.22-1ubuntu2.13 | USN-4456-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | dovecot | 1:2.2.9-1ubuntu2.6+esm3 | USN-4456-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | dovecot +4 | 1:2.3.8-2.el8_2.2 | RHSA-2020:3713 |
| RHEL 7 | dovecot +4 | 1:2.2.36-6.el7_8.1 | RHSA-2020:3617 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.1 EUS | dovecot +4 | 1:2.2.36-10.el8_1.2 | RHSA-2020:3736 |
| RHEL 8.0 E4S | dovecot +2 | 1:2.2.36-5.el8_0.3 | RHSA-2020:3735 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | dovecot23 | 2.3.11.3-17.5.1 | SUSE-SU-2021:0028-1 |
| SLES 15 SP1 | dovecot23 | 2.3.10-16.1 | SUSE-SU-2020:2267-1 |
| SLES 15 | dovecot23 | 2.3.10-4.27.1 | SUSE-SU-2020:2266-1 |
| SLES 12 SP5 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES 12 SP4 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES 12 SP2 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES for SAP 15 | dovecot23 | 2.3.10-4.27.1 | SUSE-SU-2020:2266-1 |
| SLES for SAP 12 SP5 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES for SAP 12 SP4 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES for SAP 12 SP3 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLES for SAP 12 SP2 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SLE HPC 15 | dovecot23 | 2.3.10-4.27.1 | SUSE-SU-2020:2266-1 |
| SUSE OpenStack Cloud Crowbar 9 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE OpenStack Cloud Crowbar 8 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE OpenStack Cloud 9 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE OpenStack Cloud 8 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE OpenStack Cloud 7 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE HPE Helion OpenStack 8 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
| SUSE Enterprise Storage 5 | dovecot22 | 2.2.31-19.22.1 | SUSE-SU-2020:2274-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dovecot23 | 2.3.16-1.6 | openSUSE-SU-2024:10726-1 |
| openSUSE Tumbleweed | dovecot24 | 2.4.0-1.1 | openSUSE-SU-2025:14715-1 |
| openSUSE Leap 15.2 | dovecot23 | 2.3.10-lp152.2.3.1 | openSUSE-SU-2020:1262-1 |
| openSUSE Leap 15.1 | dovecot23 | 2.3.10-lp151.2.12.1 | openSUSE-SU-2020:1241-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.23 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.22 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.21 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.20 | dovecot | 2.3.11.3-r0 | — |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.18 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.17 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.16 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.15 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.14 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.13 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.12 | dovecot | 2.3.11.3-r0 | — |
| Alpine v3.11 | dovecot | 2.3.10.1-r1 | — |
| Alpine v3.10 | dovecot | 2.3.10.1-r1 | — |
| Alpine v3.9 | dovecot | 2.3.10.1-r1 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | dovecot +4 | 1:2.2.36-6.amzn2.1 | ALAS2-2020-1489 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | dovecot +4 | 1:2.3.8-2.el8_2.2 | ELSA-2020-3713 |
| Oracle Linux 7 | dovecot +4 | 1:2.2.36-6.el7_8.1 | ELSA-2020-3617 |
Advisories 20
- WID-SEC-2025-0235 Dovecot: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Aug 10, 2026
- RHSA-2020:3736 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:3617 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2020:3713 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4456-2 dovecot vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-4456-1 dovecot vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4745-1 dovecot - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2328-1 dovecot - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:1241-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2267-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2266-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0028-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2025:14715-1 dovecot24-2.4.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2274-1 Security update for dovecot22 SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2020:3735 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2020:1262-1 Security update for dovecot23 SUSE / openSUSE Security Updates · May 7, 2025
- openSUSE-SU-2024:10726-1 dovecot23-2.3.16-1.6 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ALAS2-2020-1489 Important: dovecot security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 16, 2020
- ELSA-2020-3713 Important: dovecot security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Sep 11, 2020
- ELSA-2020-3617 Important: dovecot security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Sep 3, 2020
References
- https://dovecot.org/security
- https://www.openwall.com/lists/oss-security/2020/08/12/2
- DSA-4745 vendor-advisory
- [debian-lts-announce] 20200815 [SECURITY] [DLA 2328-1] dovecot security update mailing-list
- USN-4456-1 vendor-advisory
- USN-4456-2 vendor-advisory
- openSUSE-SU-2020:1241 vendor-advisory
- openSUSE-SU-2020:1262 vendor-advisory
- FEDORA-2020-cd8b8f887b vendor-advisory
- GLSA-202009-02 vendor-advisory
- FEDORA-2020-b8ebc4201e vendor-advisory
- FEDORA-2020-d737c57172 vendor-advisory