Description
An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Using excessive bracing, attacker can cause memory usage up to configured memory limit. Install fixed version, or configure vsz_limit for imap process to low value. No publicly available exploits are known.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Open-Xchange | OX Dovecot Pro | ≤ 3.0.5, ≤ 3.1.4, ≤ 2.4.3 | — |
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 | 1:2.4.4+dfsg1-1 | — |
| Debian 13 | dovecot | 1:2.4.1+dfsg1-6+deb13u6 | — |
| Debian 12 | dovecot | 1:2.3.19.1+dfsg1-2.1+deb12u6 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | dovecot | 1:2.4.2+dfsg1-3ubuntu2.1 | — |
| Ubuntu 25.10 | dovecot | 1:2.4.1+dfsg1-5ubuntu4.2 | — |
| Ubuntu 24.04 LTS | dovecot | 1:2.3.21+dfsg1-2ubuntu6.5 | — |
| Ubuntu 22.04 LTS | dovecot | 1:2.3.16+dfsg1-3ubuntu2.9 | — |
| Ubuntu 20.04 LTS | dovecot | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | dovecot | No fix yet | — |
| Ubuntu 16.04 LTS | dovecot | No fix yet | — |
| Ubuntu Pro 14.04 LTS | dovecot | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | dovecot +4 | 1:2.3.21-19.el10_2.1 | RHSA-2026:41988 |
| RHEL 9 | dovecot +4 | 1:2.3.16-18.el9_8.1 | RHSA-2026:41905 |
| RHEL 8 | dovecot +4 | 1:2.3.16-8.el8_10 | RHSA-2026:46532 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | dovecot | 1:2.3.21-16.el10_0.2 | RHSA-2026:42091 |
| RHEL 9.6 EUS | dovecot | 1:2.3.16-15.el9_6.2 | RHSA-2026:44355 |
| RHEL 9.4 E4S | dovecot | 1:2.3.16-11.el9_4.3 | RHSA-2026:44357 |
| RHEL 9.2 E4S | dovecot | 1:2.3.16-8.el9_2.3 | RHSA-2026:44373 |
| RHEL 8.8 TUS | dovecot | 1:2.3.16-3.el8_8.2 | RHSA-2026:46381 |
| RHEL 8.8 E4S | dovecot | 1:2.3.16-3.el8_8.2 | RHSA-2026:46381 |
| RHEL 8.6 EUS Long Life | dovecot | 1:2.3.16-2.el8_6.2 | RHSA-2026:46379 |
| RHEL 8.6 AUS | dovecot | 1:2.3.16-2.el8_6.2 | RHSA-2026:46379 |
| RHEL 8.4 EUS Long Life | dovecot | 1:2.3.8-9.el8_4.2 | RHSA-2026:46380 |
| RHEL 8.4 AUS | dovecot | 1:2.3.8-9.el8_4.2 | RHSA-2026:46380 |
| RHEL 7 ELS | dovecot | 1:2.2.36-8.el7_9.2 | RHSA-2026:49513 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | dovecot +4 | 1:2.3.21-19.el10_2.1 | ALSA-2026:41988 |
| AlmaLinux 9 | dovecot +4 | 1:2.3.16-18.el9_8.1 | ALSA-2026:41905 |
| AlmaLinux 8 | dovecot +4 | 1:2.3.16-8.el8_10 | ALSA-2026:46532 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | dovecot | 1:2.3.21-19.el10_2.1 | RLSA-2026:41988 |
| Rocky Linux 9 | dovecot | 1:2.3.16-18.el9_8.1 | RLSA-2026:41905 |
| Rocky Linux 8 | dovecot | 1:2.3.16-8.el8_10 | RLSA-2026:46532 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 12 SP5 | dovecot22 | 2.2.31-19.37.2 | SUSE-SU-2026:2645-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | dovecot24 | 2.4.4-160000.1.1 | SUSE-SU-2026:22185-1 |
| SLES for SAP 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES for SAP 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES for SAP 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 16.0 | dovecot24 | 2.4.4-160000.1.1 | SUSE-SU-2026:22185-1 |
| SLE HPC 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLE HPC 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dovecot24 | 2.4.4-1.1 | openSUSE-SU-2026:10766-1 |
| openSUSE Leap 16.0 | dovecot24 | 2.4.4-160000.1.1 | openSUSE-SU-2026:21109-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dovecot | 2.4.4-r0 | — |
| Alpine v3.23 | dovecot | 2.4.4-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | dovecot | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | dovecot +4 | 1:2.3.21-19.el10_2.1 | ELSA-2026-41988 |
| Oracle Linux 9 | dovecot +4 | 1:2.3.16-18.el9_8.1 | ELSA-2026-41905 |
| Oracle Linux 8 | dovecot +4 | 1:2.3.16-8.el8_10 | ELSA-2026-46532 |
| Oracle Linux 7 | dovecot +4 | 1:2.2.36-8.0.3.el7 | ELSA-2026-49513 |
Advisories 27
- ALSA-2026:41905 Important: dovecot security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:41988 Important: dovecot security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:46532 Important: dovecot security update AlmaLinux Security Advisories · Oct 29, 2026
- SUSE-SU-2026:4139-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Sep 28, 2026
- WID-SEC-2026-1510 OX Dovecot Pro: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 21, 2026
- ELSA-2026-49513 Important: dovecot security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Aug 10, 2026
- RHSA-2026:49513 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:46532 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:46380 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:46381 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:46379 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:44373 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:44357 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:44355 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:42091 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:41988 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RHSA-2026:41905 Red Hat Security Advisory: dovecot security update Red Hat Security Advisories (RHSA) · Aug 4, 2026
- RLSA-2026:46532 Important: dovecot security update Rocky Linux Security Advisories · Jul 28, 2026
- ELSA-2026-46532 Important: dovecot security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jul 28, 2026
- RLSA-2026:41988 Important: dovecot security update Rocky Linux Security Advisories · Jul 22, 2026
- RLSA-2026:41905 Important: dovecot security update Rocky Linux Security Advisories · Jul 22, 2026
- ELSA-2026-41988 Important: dovecot security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 20, 2026
- ELSA-2026-41905 Important: dovecot security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 20, 2026
- openSUSE-SU-2026:21109-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:2645-1 Security update for dovecot22 SUSE / openSUSE Security Updates · Jun 27, 2026
- SUSE-SU-2026:22185-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:10766-1 dovecot24-2.4.4-1.1 on GA media SUSE / openSUSE Security Updates · May 14, 2026