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CVE-2026-99217
fork: release the files of a failed fork after sched_cancel_fork()
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: fork: release the files of a failed fork after sched_cancel_fork() Reorder copy_process() cleanup so sched_fork() taking scx_fork_rwsem scx_pre_fork() is safe and isn't held around exiting files. Right now, a fork that fails while another thread closed the bpf link fd will deadlock against its own read side. It also blocks every fork on the system: copy_process() holds scx_fork_rwsem for read exit_files() close_files() filp_close_sync() bpf_scx_unreg() kthread_flush_work() waits for the disable work scx_root_disable() percpu_down_write(&scx_fork_rwsem) Simply release the child's files after sched_cancel_fork() dropped the lock. The task starts out as a copy of its parent so p->files points to the parent's table until copy_files() replaces it. exit_files() must not run for a fork that failed before that. Clear p->files up front so exit_files() is a no-op for those and make copy_files() set it explicitly for CLONE_FILES.

Details
INFO

Published Date :

Nov. 2, 2026, 4:17 p.m.

Last Modified :

Nov. 2, 2026, 4:17 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-99217 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Address a deadlock in the fork process by releasing files after lock acquisition.
  • Ensure files are released after sched_cancel_fork() drops the lock.
  • Clear p->files upfront to prevent issues during fork failure.
  • Make copy_files() explicitly set p->files for CLONE_FILES.
  • Reorder copy_process() cleanup for sched_fork() safety.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-99217.

URL Resource
https://git.kernel.org/stable/c/14c7de6ca239326b79fd3f7aee55dfada1bb72ab
https://git.kernel.org/stable/c/27e1cbf8ec5f7117f6bb2d2e44030ac055f09097
https://git.kernel.org/stable/c/afa8eb069694bd9f845e5e44eac6e81cbc06780e
https://git.kernel.org/stable/c/f7ac8500d58e7684d37403553b1dea90ee2b27b1
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-99217 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-99217 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-99217 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-99217 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Nov. 02, 2026

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: fork: release the files of a failed fork after sched_cancel_fork() Reorder copy_process() cleanup so sched_fork() taking scx_fork_rwsem scx_pre_fork() is safe and isn't held around exiting files. Right now, a fork that fails while another thread closed the bpf link fd will deadlock against its own read side. It also blocks every fork on the system: copy_process() holds scx_fork_rwsem for read exit_files() close_files() filp_close_sync() bpf_scx_unreg() kthread_flush_work() waits for the disable work scx_root_disable() percpu_down_write(&scx_fork_rwsem) Simply release the child's files after sched_cancel_fork() dropped the lock. The task starts out as a copy of its parent so p->files points to the parent's table until copy_files() replaces it. exit_files() must not run for a fork that failed before that. Clear p->files up front so exit_files() is a no-op for those and make copy_files() set it explicitly for CLONE_FILES.
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99217.json">CVE-2026-99217</a>
    Added Reference https://git.kernel.org/stable/c/14c7de6ca239326b79fd3f7aee55dfada1bb72ab
    Added Reference https://git.kernel.org/stable/c/27e1cbf8ec5f7117f6bb2d2e44030ac055f09097
    Added Reference https://git.kernel.org/stable/c/afa8eb069694bd9f845e5e44eac6e81cbc06780e
    Added Reference https://git.kernel.org/stable/c/f7ac8500d58e7684d37403553b1dea90ee2b27b1
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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