CVE-2026-72104 dm-pcache: reject option groups without values
A local attacker can cause a kernel crash by providing malformed device-mapper pcache table arguments, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72104?
CVE-2026-72104 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dm-pcache: reject option groups without values
The pcache target parses optional arguments as name/value pairs. A table that advertises one optional argument and supplies only a recognized option name, for example "cache_mode", reaches parse_cache_opts() with argc == 1. The parser consumes the name, decrements argc to zero, then calls dm_shift_arg() again for the value. dm_shift_arg() returns NULL when no arguments remain, and the following strcmp() dereferences that NULL pointer.
Check that each recognized option has a value before consuming it. This keeps valid "cache_mode writeback" and "data_crc true/false" tables unchanged while making malformed tables fail during target construction with a precise missing-value error.
Which versions are affected by CVE-2026-72104?
How do I fix CVE-2026-72104?
Apply the vendor's patch.
Is CVE-2026-72104 being exploited?
There is no known exploitation of CVE-2026-72104 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72104, DEBIAN-CVE-2026-72104, GHSA-3wp6-4r9h-frm7, UBUNTU-CVE-2026-72104.