CVE-2026-72155 mtd: spi-nor: swp: Improve locking user experience
A logic error in the Linux kernel SPI-NOR driver prevents unlocking specific locked blocks, requiring a patch to correct the lock length calculation.
- 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-2026-72155?
CVE-2026-72155 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:
mtd: spi-nor: swp: Improve locking user experience
In the case of the first block being locked (or the few first blocks), if the user want to fully unlock the device it has two possibilities: - either it asks to unlock the entire device, and this works; - or it asks to unlock just the block(s) that are currently locked, which fails.
It fails because the conditions "can_be_top" and "can_be_bottom" are true. Indeed, in this case, we unlock everything, so the TB bit does not matter. However in the current implementation, use_top would be true (as this is the favourite option) and lock_len, which in practice should be reduced down to 0, is set to "nor->params->size - (ofs + len)" which is a positive number. This is wrong.
An easy way is to simply add an extra condition. In the unlock() path, if we can achieve the same result from both sides, it means we unlock everything and lock_len must simply be 0. A comment is added to clarify that logic.
Which versions are affected by CVE-2026-72155?
How do I fix CVE-2026-72155?
Apply the vendor's patch.
Is CVE-2026-72155 being exploited?
There is no known exploitation of CVE-2026-72155 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72155, DEBIAN-CVE-2026-72155, GHSA-4g3m-gr2j-r4mp, UBUNTU-CVE-2026-72155.