CVEvulnerability
CVE-2026-67194
7.1 HIGH
Official page ↗
- Status
- Deferred
- Published
- 2026-07-29
- Last modified
- 2026-07-30
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 7.1 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-674
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.
Related
Weakness · CWE (1)
- CWE-674 Uncontrolled Recursion weakness
References
- https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e github.com
- https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309 github.com
- https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444 github.com
- https://packages.debian.org/sid/courier-imap packages.debian.org
- https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries www.vulncheck.com