An attacker that has valid credentials can use IMAP LIST command to consume CPU.

Versions reported by the vendor

Affected version ranges reported by the assigning authority (OX). Independent of NVD's CPE analysis and usually ahead of it.

• Open-Xchange GmbH OX Dovecot CE

  • 2.3.0 and later · before 2.4.5affected · semver

• Open-Xchange GmbH OX Dovecot Pro

  • 2.3.0 and later · before 3.0.7affected · semver
  • 3.1.0 and later · before 3.1.6affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2026-42007An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing
  36Monitor
• CVE-2026-42391An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CP
  30Monitor
• CVE-2026-33605An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating.
  30Monitor
• CVE-2026-27852An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME parameters
  30Monitor
• CVE-2024-23185Very large headers can cause resource exhaustion when parsing message.
  30Monitor
• CVE-2026-73208An attacker that holds a token intended for a different purpose can authenticate, because when an OAuth2 token response does not contain a s
  29Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1function expand(node) {2  return node.children.map(expand);3}

1const MAX_DEPTH = 32;2function expand(node, depth = 0) {3  if (depth > MAX_DEPTH) throw new Error("too deep");4  return node.children.map((c) => expand(c, depth + 1));5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.