CVE-2026-67194

MediumCVSS 6.5/10Last modified Jul 30, 2026

Description

Courier IMAP before 6.0.1 and Courier Mail Server before 2.0.2 allow authenticated IMAP users to crash the imapd process via deeply nested parenthesized SEARCH queries. The SEARCH command parser (alloc_search_key in searchinfo.C) recursively descends on nested parenthesized groups through a mutual recursion chain with alloc_search_andlist() and alloc_search_notkey(), with no depth limit. Courier IMAP has no overall command line length limit, making exploitation trivial. A single IMAP command with ~2500 nested parentheses overflows the 8MB default stack, causing SIGSEGV.

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

Affected software

No affected versions have been published.

Timeline

Published
Jul 29, 2026
Last modified
Jul 30, 2026
NVD status
Deferred

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CVE-2026-67194: Medium severity, CVSS 6.5 | Vulnix