Time-of-check Time-of-use (TOCTOU) Affecting kernel-rt-modules-internal package, versions *


Severity

Recommended
0.0
high
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.65% (49th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-CENTOS8-KERNELRTMODULESINTERNAL-20101110
  • published24 Sept 2026
  • disclosed11 Sept 2026

Introduced: 11 Sep 2026

NewCVE-2026-89713  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-rt-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-modules-internal package and not the kernel-rt-modules-internal package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

NFSD: check truncate permission under inode lock

nfsd_setattr() checks whether a size update needs NFSD_MAY_TRUNC before it takes inode_lock(). The comparison uses the file size sampled by that unlocked read, but the actual ATTR_SIZE update is applied later under inode_lock() by notify_change().

This leaves a TOCTOU window for append-only files. If a client sends a SETATTR that does not shrink the file at the time of the unlocked sample, a concurrent append can extend the file before nfsd_setattr() takes inode_lock(). notify_change() then applies a real truncation without the NFSD_MAY_TRUNC check that rejects IS_APPEND(inode). The VFS truncate syscall paths perform their own append-only checks before calling notify_change(), so NFSD must make this decision against the locked size it is about to change.

Split the write-count acquisition from the truncation permission check. Keep get_write_access() before the locked setattr work, then recheck whether the requested size is below i_size_read(inode) after inode_lock() has been acquired and before notify_change(ATTR_SIZE). This also avoids the plain unlocked inode->i_size load.

CVSS Base Scores

version 3.1