High · CVSS 7.8CVE-2026-23415

futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()CVE-2026-23415

Answer in brief

CVE-2026-23415 records a High severity (CVSS 7.8) vulnerability in futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Apr 2, 2026Updated Oct 16, 2026Source checked Oct 16, 2026First seen by HOL Oct 16, 2026Material review Oct 16, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=c042c505210dc3453f378df432c10fff3d471bc5 <853f70c67d1b37e368fdcb3e328c4b8c04f53ac0 \|\| >=c042c505210dc3453f378df432c10fff3d471bc5 <7e196194ea27bd49adf3551e2aceb83498eb73fe \|\| >=c042c505210dc3453f378df432c10fff3d471bc5 <190a8c48ff623c3d67cb295b4536a660db2012aa	853f70c67d1b37e368fdcb3e328c4b8c04f53ac0, 7e196194ea27bd49adf3551e2aceb83498eb73fe, 190a8c48ff623c3d67cb295b4536a660db2012aa
Linux/Linuxgeneric	6.16	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 853f70c67d1b37e368fdcb3e328c4b8c04f53ac0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Apr 2, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 16, 2026

Sources and claim methodology

Upstream source description

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().

Quoted source text, attributed separately from HOL analysis.