Improper control of a resource through its lifetime in Linux kernel - CVE-2026-89987
Published: September 16, 2026
Vulnerability identifier: #VU150305
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89987
CWE-ID: CWE-664
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause silent data loss.
The vulnerability exists due to failure to propagate the PMD dirty bit in zap_huge_pmd_folio() when unmapping a PMD-mapped MAP_SHARED tmpfs mapping after data has been written through a read-faulted mapping. A local user can write data through a shared tmpfs mapping and unmap it to cause silent data loss.
Exploitation requires shmem transparent huge pages and swap to be enabled.
Affected software
Linux kernel
How to mitigate CVE-2026-89987
Install security update from vendor's repository.