CVE-2026-53189 mm/huge_memory: update file PMD counter before folio_put()
A use-after-free in the Linux kernel's huge memory management allows attackers to potentially execute code or escalate privileges by triggering a race condition during PMD splitting.
- 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-2026-53189?
CVE-2026-53189 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 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:
mm/huge_memory: update file PMD counter before folio_put()
__split_huge_pmd_locked() updates the file/shmem RSS counter after dropping the PMD mapping's folio reference. If folio_put() drops the last reference, mm_counter_file() can later read freed folio state via folio_test_swapbacked().
Move the counter update before folio_put().
Weakness: CWE-416
Which versions are affected by CVE-2026-53189?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53189?
Apply the vendor's patch.
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-2026-53189 being exploited?
There is no known exploitation of CVE-2026-53189 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90707, BELL-CVE-2026-53189, DEBIAN-CVE-2026-53189, GHSA-g27r-592c-r436, ROOT-OS-DEBIAN-11-CVE-2026-53189, ROOT-OS-DEBIAN-12-CVE-2026-53189 and 3 more.