CVE-2026-46259
Analyzed Analyzed - Analysis Complete
Race Condition in Linux Kernel procfs Real-Parent Access

Publication date: 2026-06-03

Last updated on: 2026-06-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: procfs: fix missing RCU protection when reading real_parent in do_task_stat() When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent without proper RCU protection, which leads to: cpu 0 cpu 1 ----- ----- do_task_stat var = task->real_parent release_task call_rcu(delayed_put_task_struct) task_tgid_nr_ns(var) rcu_read_lock <--- Too late to protect task->real_parent! task_pid_ptr <--- UAF! rcu_read_unlock This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add proper RCU protection for accessing task->real_parent.
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Meta Information
Published
2026-06-03
Last Modified
2026-06-09
Generated
2026-06-24
AI Q&A
2026-06-03
EPSS Evaluated
2026-06-22
NVD
CVE-2026-46259
EUVD
EUVD-2026-34121
Affected Vendors & Products
Showing 7 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.13 (inc) to 6.18.14 (exc)
linux linux_kernel From 6.19 (inc) to 6.19.4 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.128 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.75 (exc)
linux linux_kernel From 5.11 (inc) to 5.15.202 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.165 (exc)
linux linux_kernel From 2.6.26 (inc) to 5.10.252 (exc)
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's procfs subsystem, specifically in the function do_task_stat() which reads the /proc/[pid]/stat file.

The issue is that do_task_stat() accesses the real_parent field of a task structure without proper Read-Copy-Update (RCU) protection. This improper handling can lead to a use-after-free (UAF) condition because the real_parent pointer might be freed or modified concurrently.

The vulnerability arises because the RCU read lock is applied too late, after accessing the real_parent pointer, which means the pointer can become invalid during the access.

The fix involves using task_ppid_nr_ns() instead of task_tgid_nr_ns() to ensure proper RCU protection when accessing real_parent, preventing the use-after-free scenario.

Mitigation Strategies

The vulnerability is fixed by applying the patch that changes the access method in do_task_stat() to use task_ppid_nr_ns() instead of task_tgid_nr_ns(), ensuring proper RCU protection when reading task->real_parent.

Therefore, the immediate step to mitigate this vulnerability is to update the Linux kernel to a version that includes this fix.

Impact Analysis

This vulnerability can lead to a use-after-free condition in the Linux kernel when reading process information from /proc/[pid]/stat.

A use-after-free can cause kernel memory corruption, which may result in system instability, crashes, or potentially allow an attacker to execute arbitrary code with kernel privileges.

Exploitation of this vulnerability could compromise the security and reliability of the affected system.

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