CVE-2026-67194:
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.
Lintian reports
1 warning
about this package. You should make the package lintian clean getting rid of them.
debian/patches: 19 patches to forward upstream
low
Among the 23 debian patches
available in version 2.0.6-1 of the package,
we noticed the following issues:
19 patches
where the metadata indicates that the patch has not yet been forwarded
upstream. You should either forward the patch upstream or update the
metadata to document its real status.
testing migrations
This package will soon be part of the auto-perl transition. You might want to ensure that your package is ready for it.
You can probably find supplementary information in the
debian-release
archives or in the corresponding
release.debian.org
bug.
![[bug history graph]](https://qa.debian.org/data/bts/graphs/c/courier.png){kind=link}