Allocation of Resources Without Limits or Throttling Affecting dovecot/pigeonhole package, versions [,2.4.3)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published2 Apr 2026
- disclosed27 Mar 2026
- creditUnknown
Introduced: 27 Mar 2026
CVE-2026-27858 (opens in a new tab)How to fix?
Upgrade dovecot/pigeonhole to version 2.4.3 or higher.
Overview
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the managesieve-login during authentication. An attacker can exhaust system memory and cause service unavailability by sending specially crafted messages before authentication, leading to repeated crashes of the managesieve-login.
Workaround
This vulnerability can be mitigated by configuring firewall rules to restrict access to the managesieve port and only allow connections from trusted IP addresses or networks.