CVE-2026-40203
An attacker can exploit multiple vulnerabilities in Dovecot to bypass security measures, disclose sensitive information, manipulate data, or cause denial-of-service conditions.
CSIRTS triage
- What
- Dovecot contains multiple vulnerabilities allowing attackers to bypass security measures, disclose sensitive information, manipulate data, or cause denial-of-service.
- Who is affected
- All Dovecot mail server deployments running affected versions.
- Urgency
- High; multiple unpatched vulnerabilities affecting a critical email infrastructure component.
- Action
- Update Dovecot to the latest version addressing CVE-2023-51764, CVE-2023-51766, and CVE-2026-27852 through CVE-2026-33607.
AI-assisted analysis generated from the source advisory — verify against the original.
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Advisory coverage (2)
- high[NEW] [high] Dovecot: Multiple vulnerabilitiescert-bund · 2026-08-31
- lowCVE-2026-40203: When IMAP compression is enabled, the same compression state is reused across responses in a s…nvd · 2026-08-28
External references
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[](https://www.csirts.com/cve/CVE-2026-40203)