CVE-2026-99218
Received Received - Intake

RCU Use-After-Free in Linux Kernel coredump

Publication date: 2026-11-02

Last updated on: 2026-11-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: coredump: hold RCU while releasing parked threads coredump_finish() releases the parked threads by clearing ->task in their core_thread entry and calling wake_up_process() on each of them. It does that without holding a reference on the task and without being inside rcu. But calling wake_up_process(task) without rcu here isn't safe. A parked thread doesn't need that wakeup to leave. A spurious wakeup or a preemption after the store is enough for the task to go away. So if the coredump client is preempted between the store and wake_up_process() the thread can exit and be freed in the meantime and try_to_wake_up() takes pi_lock in freed memory. Hold rcu across the loop.

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Meta Information

Published
2026-11-02
Last Modified
2026-11-02
Generated
2026-11-02
AI Q&A
2026-11-02
EPSS Evaluated
N/A
NVD
CVE-2026-99218

Affected Vendors & Products

Showing 7 associated CPEs
Vendor Product Version / Range
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux a94e2d408eaedbd85aae259621d46fafc10479a2
Linux Linux 2.6.27

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the coredump functionality. The issue occurs when coredump_finish() releases parked threads without holding an RCU reference or being in an RCU context. This can lead to a situation where a parked thread exits and is freed before wake_up_process() is called, causing a use-after-free scenario when trying to wake the thread.

Detection Guidance

This vulnerability is specific to the Linux kernel's coredump mechanism and requires kernel-level inspection. Detection involves checking kernel logs for coredump-related errors or crashes, particularly after system calls that trigger coredumps. Commands like 'dmesg | grep -i coredump' or 'journalctl -k | grep -i coredump' may reveal issues. Ensure your kernel is updated to a patched version.

Impact Analysis

This vulnerability could allow an attacker with local access to cause a denial of service or potentially execute arbitrary code on the affected system. The impact includes system instability, crashes, or unauthorized code execution due to memory corruption.

Compliance Impact

This vulnerability affects compliance with standards like GDPR and HIPAA by potentially enabling unauthorized access to sensitive data through kernel memory corruption during core dumps. The flaw allows race conditions that could lead to privilege escalation or information disclosure, violating confidentiality and integrity requirements in these regulations.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the coredump vulnerability. Monitor system logs for unusual activity related to coredump processes.

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