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
Affected Vendors & Products
References
History
Wed, 29 Jul 2026 18:30:00 +0000
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Wed, 29 Jul 2026 17:15:00 +0000
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| 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. | |
| Title | Courier IMAP < 6.0.1 Mail Server < 2.0.2 Stack Overflow DoS via Nested SEARCH Queries | |
| Weaknesses | CWE-674 | |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-07-29T18:07:09.182Z
Reserved: 2026-07-28T16:06:49.774Z
Link: CVE-2026-67194
Updated: 2026-07-29T18:07:04.575Z
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OpenCVE Enrichment
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