Use After Free in Linux
CVE-2026-23415
In the Linux kernel, the following vulnerability has been resolved: futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy() During futex_key_to_node_opt() execution, vma->vm_policy is read under speculative mmap lock and RCU. Concurrently, mbind() may call vma_replace_policy() which frees the old mempolicy immediately via kmem_cache_free(). This creates a race where __futex_key_to_node() dereferences a freed mempolicy pointer, causing a use-after-free read of mpol->mode. [ 151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349) [ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87 [ 151.415969] Call Trace: [ 151.416732] __asan_load2 (mm/kasan/generic.c:271) [ 151.416777] __futex_key_to_node (kernel/futex/core.c:349) [ 151.416822] get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593) Fix by adding rcu to __mpol_put().
Vulnerability class: Use-After-Free
EPSS: 0.001 (3.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Linux — versions c042c505210dc3453f378df432c10fff3d471bc5, 6.16, 0
- Linux Linux_kernel — versions 6.16, 7.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2026-23415?
- CVE-2026-23415 is a high-severity vulnerability in Linux, classified under Use After Free. CVSS score: 7.8/10. Published 2026-04-02.
- How severe is CVE-2026-23415?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2026-23415 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.