CVE-2026-61915 Use after free in Cyrus IMAP
An authenticated user can crash the CalDAV worker via a double-free vulnerability in Cyrus IMAP, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61915?
CVE-2026-61915 is a medium-severity use after free vulnerability in cyrusimap Cyrus IMAP, published on 9 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An issue was discovered in Cyrus IMAP before 3.12.4. There is a VPATCH BYPARAM double-free. An authenticated calendar user could crash a Cyrus CalDAV worker with a PATCH containing PATCH-ACTION="BYPARAM@..." against a resource with two or more properties of the matched kind. The memory holding the selector would be freed once on each iteration over the properties.
Weakness: CWE-415
Which versions are affected by CVE-2026-61915?
It affects 1 product.
Products include Cyrus Imap.
How do I fix CVE-2026-61915?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-61915 being exploited?
There is no known exploitation of CVE-2026-61915 in the wild and no public exploit code.
Other vulnerabilities in cyrusimap Cyrus IMAP
Sources
Also known as CLSA-2026-1790252040, CLSA-2026-1790758129, CLSA-2026-1790764098, CLSA-2026-1790764490, CLSA-2026-1790769478, CLSA-2026-1790963865 and 5 more.