CVE-2026-90188 null_blk: free global tag_set on init error path
A memory leak in the Linux kernel null_blk driver occurs when device creation fails with shared tags enabled, potentially leading to resource exhaustion.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90188?
CVE-2026-90188 is a memory corruption vulnerability in Linux, published on 17 Sep 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:
null_blk: free global tag_set on init error path
If shared_tags is enabled, null_setup_tagset() allocates the global tag_set via null_init_global_tag_set(). If device creation later fails, err_dev destroys the default devices and calls unregister_blkdev(), but never frees the global tag_set. Since module init failed, null_exit() is never invoked, so the global tag_set's tags and maps are permanently leaked.
Free the global tag_set in err_dev, matching null_exit() which does if (tag_set.ops) blk_mq_free_tag_set(&tag_set).
Which versions are affected by CVE-2026-90188?
How do I fix CVE-2026-90188?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-90188 being exploited?
There is no known exploitation of CVE-2026-90188 in the wild and no public exploit code.
Sources
Also known as AZL-102242, BELL-CVE-2026-90188, DEBIAN-CVE-2026-90188, GHSA-jmg2-qcvp-f7gg, UBUNTU-CVE-2026-90188.