CyberSecBulletin
CVE-2026-72034NVD status: Received

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2026-72034 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 15104234c267ebe04b9f9a73e5c2179cc265ff60, 6c52226072a3c61337b1eec1799bb987748884fa, 6ee183d89261bf1d1cf9f06d80a40dab8f36ee55 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.18% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 15104234c267ebe04b9f9a73e5c2179cc265ff60 or 6c52226072a3c61337b1eec1799bb987748884fa or 6ee183d89261bf1d1cf9f06d80a40dab8f36ee55 or 6c732471740bc2ac9b0946134f9f551dc75f4369, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux620c266f394932e5decc4b34683a75dfc59dc2f4 up to, but not including, 15104234c267ebe04b9f9a73e5c2179cc265ff60; 620c266f394932e5decc4b34683a75dfc59dc2f4 up to, but not including, 6c52226072a3c61337b1eec1799bb987748884fa; 620c266f394932e5decc4b34683a75dfc59dc2f4 up to, but not including, 6ee183d89261bf1d1cf9f06d80a40dab8f36ee55; 620c266f394932e5decc4b34683a75dfc59dc2f4 up to, but not including, 6c732471740bc2ac9b0946134f9f551dc75f4369; 6.1115104234c267ebe04b9f9a73e5c2179cc265ff60, 6c52226072a3c61337b1eec1799bb987748884fa, 6ee183d89261bf1d1cf9f06d80a40dab8f36ee55, 6c732471740bc2ac9b0946134f9f551dc75f4369

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: fhandle: reject detached mounts in capable_wrt_mount() The recent fhandle RCU fix moved the mount namespace capability check into capable_wrt_mount(), so a non-NULL mnt_namespace survives the ns_capable() dereference. The helper still assumes the later READ_ONCE(mount->mnt_ns) must be non-NULL because may_decode_fh() checked is_mounted() first. That assumption is not stable. A detached mount from open_tree(..., OPEN_TREE_CLONE) can be dissolved on fput while open_by_handle_at() is between those checks, and umount_tree() can clear mount->mnt_ns. If the helper observes NULL, it dereferences mnt_ns->user_ns and panics. Return false when the RCU read observes a detached mount. This keeps the relaxed permission path conservative: a mount no longer attached to a namespace cannot authorize open_by_handle_at() access.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent NULL Pointer Dereference vulnerabilities

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