CVE-2026-27857
4.3 · MEDIUMOverview
CVE-2026-27857 is a medium-severity vulnerability affecting dovecot dovecot. It was published on March 27, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
Remediation
Check the references section for vendor advisories and patches from dovecot. Update dovecot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| dovecot | dovecot | >= 0, < 2.4.3 | Affected |
| open-xchange | dovecot | >= 0, < 2.3.22.1 | Affected |
References
Frequently Asked Questions
What is CVE-2026-27857?
CVE-2026-27857 is a medium-severity vulnerability affecting dovecot dovecot. It was published on March 27, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).
How severe is CVE-2026-27857?
This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-27857?
Check the references section for vendor advisories and patches from dovecot. Update dovecot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-27857?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-27857 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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