CVE-2026-43292

MEDIUM EPSS 2.3%
Published May 8, 20261mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published May 8, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during vmalloc cleanup triggers expensive stack unwinding that acquires RCU read locks. Processing a large purge_list without rescheduling can cause the task to hold CPU for extended periods (10+ seconds), leading to RCU stalls and potential OOM conditions. The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node() where iterating through hundreds or thousands of vmap_area entries and freeing their associated shadow pages causes: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l ... task:kworker/0:17 state:R running task stack:28840 pid:6229 ... kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299 purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 Each call to kasan_release_vmalloc() can free many pages, and with page_owner tracking, each free triggers save_stack() which performs stack unwinding under RCU read lock. Without yielding, this creates an unbounded RCU critical section. Add periodic cond_resched() calls within the loop to allow: - RCU grace periods to complete - Other tasks to run - Scheduler to preempt when needed The fix uses need_resched() for immediate response under load, with a batch count of 32 as a guaranteed upper bound to prevent worst-case stalls even under light load.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
2.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 3

VendorProductVersionRange
linuxlinux_kernel*≥6.9  –  <6.12.75
linuxlinux_kernel*≥6.13  –  <6.18.16
linuxlinux_kernel*≥6.19  –  <6.19.6

References 4

  • git.kernel.org https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2efa9c02c9b4c0d6866aa445f11056809b25ca28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447
    Patch