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🛡️ CVE-2023-53419 — kernel

🟡 CVSS 5.5 — Medium ✅ No Known Exploit NVD
5.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access

In the Linux kernel, the following vulnerability has been resolved:

rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access

For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can

result in a NULL-pointer dereference:

CPU1 CPU2

rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall

if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL

raw_spin_lock_rcu_node

np = rcu_next_node_entry(t, rnp)

if (&t->rcu_node_entry == rnp->exp_tasks)

WRITE_ONCE(rnp->exp_tasks, np)

....

raw_spin_unlock_irqrestore_rcu_node

raw_spin_lock_irqsave_rcu_node

t = list_entry(rnp->exp_tasks->prev,

struct task_struct, rcu_node_entry)

(if rnp->exp_tasks is NULL, this

will dereference a NULL pointer)

The problem is that CPU2 accesses the rcu_node structure's->exp_tasks

field without holding the rcu_node structure's ->lock and CPU2 did

not observe CPU1's change to rcu_node structure's ->exp_tasks in time.

Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,

then CPU2 might dereference that NULL pointer.

This commit therefore holds the rcu_node structure's ->lock while

accessing that structure's->exp_tasks field.

[ paulmck: Apply Frederic Weisbecker feedback. ]

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-53419 is recorded against 2 packages.

  • kernel (from 6.2.0 up to 6.3.4)
  • linux-kernel (from 6.2 up to 6.3.4)

Timeline and source

Published on 18 September 2025 and last revised on 12 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

Other advisories for this package

kernel has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2023-53419 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.5
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-09-18
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.2.0 6.3.4
linux-kernel 6.2 6.3.4

Similar Threats

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