Red Hat Security Advisory: dovecot security update
Multiple denial of service vulnerabilities have been identified in Dovecot, an IMAP and POP3 server for UNIX-like systems. These include a denial of service via a crafted SASL initial response in the AUTHENTICATE command (CVE-2025-59032), denial of service via a crafted message before authentication (CVE-2026-27858), and denial of service via a specially crafted NOOP command (CVE-2026-27857). Red Hat has issued an important security advisory providing updates to address these issues in Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions. The advisory rates the impact as important and provides updated packages to remediate the vulnerabilities.
AI Analysis
Technical Summary
This advisory addresses three denial of service vulnerabilities in Dovecot: CVE-2025-59032 involves the ManageSieve component where a crafted SASL initial response in the AUTHENTICATE command can cause denial of service. CVE-2026-27858 involves denial of service triggered by a crafted message before authentication. CVE-2026-27857 involves denial of service via a specially crafted NOOP command. Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions to fix these issues. The advisory references specific bugzilla entries and provides SHA-256 hashes for the updated packages. No CVSS scores are provided in the advisory, but the severity is rated as important.
Potential Impact
Successful exploitation of these vulnerabilities can cause denial of service conditions in the Dovecot server, potentially disrupting email services. The vulnerabilities affect the ManageSieve authentication mechanism and message handling before authentication, as well as the NOOP command processing. There is no indication of code execution or data disclosure. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions that address these vulnerabilities. Users should apply the provided security updates as detailed in the Red Hat advisory RHSA-2026:17630. For update instructions, refer to https://access.redhat.com/articles/11258. No additional mitigations are indicated or required beyond applying the official patches.
Red Hat Security Advisory: dovecot security update
Description
Multiple denial of service vulnerabilities have been identified in Dovecot, an IMAP and POP3 server for UNIX-like systems. These include a denial of service via a crafted SASL initial response in the AUTHENTICATE command (CVE-2025-59032), denial of service via a crafted message before authentication (CVE-2026-27858), and denial of service via a specially crafted NOOP command (CVE-2026-27857). Red Hat has issued an important security advisory providing updates to address these issues in Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions. The advisory rates the impact as important and provides updated packages to remediate the vulnerabilities.
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory addresses three denial of service vulnerabilities in Dovecot: CVE-2025-59032 involves the ManageSieve component where a crafted SASL initial response in the AUTHENTICATE command can cause denial of service. CVE-2026-27858 involves denial of service triggered by a crafted message before authentication. CVE-2026-27857 involves denial of service via a specially crafted NOOP command. Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions to fix these issues. The advisory references specific bugzilla entries and provides SHA-256 hashes for the updated packages. No CVSS scores are provided in the advisory, but the severity is rated as important.
Potential Impact
Successful exploitation of these vulnerabilities can cause denial of service conditions in the Dovecot server, potentially disrupting email services. The vulnerabilities affect the ManageSieve authentication mechanism and message handling before authentication, as well as the NOOP command processing. There is no indication of code execution or data disclosure. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions that address these vulnerabilities. Users should apply the provided security updates as detailed in the Red Hat advisory RHSA-2026:17630. For update instructions, refer to https://access.redhat.com/articles/11258. No additional mitigations are indicated or required beyond applying the official patches.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:17630
- Cve Count
- 3
- Additional Cves
- ["CVE-2026-27857","CVE-2026-27858"]
- Cvss Version
- null
Threat ID: 6a32cf7e9f87a2db092a940e
Added to database: 6/17/2026, 4:46:54 PM
Last enriched: 6/17/2026, 5:04:58 PM
Last updated: 6/17/2026, 7:14:55 PM
Views: 4
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.