Bug 2452175 (CVE-2026-27858)

Summary: CVE-2026-27858 dovecot: denial of service via crafted message before authentication
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in dovecot. An unauthenticated and remote attacker can send a crafted message that causes managesieve to allocate an excessive amount of memory, forcing managesieve-login to be unavailable by repeatedly crashing the process, resulting in a denial of service.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2452240, 2452242, 2452241    
Bug Blocks:    

Description OSIDB Bzimport 2026-03-27 09:02:09 UTC
Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory.
 Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known.

Comment 2 errata-xmlrpc 2026-05-04 13:48:46 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:13498 https://access.redhat.com/errata/RHSA-2026:13498

Comment 3 errata-xmlrpc 2026-05-05 17:11:52 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:13830 https://access.redhat.com/errata/RHSA-2026:13830

Comment 4 errata-xmlrpc 2026-05-05 19:18:28 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:13857 https://access.redhat.com/errata/RHSA-2026:13857

Comment 5 errata-xmlrpc 2026-05-14 14:00:45 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:17602 https://access.redhat.com/errata/RHSA-2026:17602

Comment 6 errata-xmlrpc 2026-05-14 15:02:27 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2026:17630 https://access.redhat.com/errata/RHSA-2026:17630

Comment 7 errata-xmlrpc 2026-05-14 15:10:19 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2026:17625 https://access.redhat.com/errata/RHSA-2026:17625

Comment 8 errata-xmlrpc 2026-05-14 15:14:05 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:17628 https://access.redhat.com/errata/RHSA-2026:17628

Comment 9 errata-xmlrpc 2026-05-14 15:24:59 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:17626 https://access.redhat.com/errata/RHSA-2026:17626

Comment 10 errata-xmlrpc 2026-05-18 12:34:13 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:18053 https://access.redhat.com/errata/RHSA-2026:18053

Comment 11 errata-xmlrpc 2026-05-19 16:09:46 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:19149 https://access.redhat.com/errata/RHSA-2026:19149

Comment 12 errata-xmlrpc 2026-05-19 21:40:41 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:19364 https://access.redhat.com/errata/RHSA-2026:19364

Comment 13 errata-xmlrpc 2026-05-20 01:56:18 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2026:19453 https://access.redhat.com/errata/RHSA-2026:19453

Comment 14 errata-xmlrpc 2026-05-20 02:07:45 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:19455 https://access.redhat.com/errata/RHSA-2026:19455