Linux: NULL Pointer Dereference
CVE-2026-31436 is a critical-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions e21da2ad8844585040fe4b82be1ad2fe99d40074, 82656e8daf8de00935ae91b91bed43f4d6e0d644, 0e4f43779d550e559be13a5cdb763bad92c4cc99 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 0.46% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to e21da2ad8844585040fe4b82be1ad2fe99d40074 or 82656e8daf8de00935ae91b91bed43f4d6e0d644 or 0e4f43779d550e559be13a5cdb763bad92c4cc99 or e1c9866173c5f8521f2d0768547a01508cb9ff27, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.80 or 6.18.21 or 6.19.11, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | aa8d18becc0c14aa3eb46d6d1b81450446e11b87 up to, but not including, e21da2ad8844585040fe4b82be1ad2fe99d40074; aa8d18becc0c14aa3eb46d6d1b81450446e11b87 up to, but not including, 82656e8daf8de00935ae91b91bed43f4d6e0d644; aa8d18becc0c14aa3eb46d6d1b81450446e11b87 up to, but not including, 0e4f43779d550e559be13a5cdb763bad92c4cc99; aa8d18becc0c14aa3eb46d6d1b81450446e11b87 up to, but not including, e1c9866173c5f8521f2d0768547a01508cb9ff27; 6.8 | e21da2ad8844585040fe4b82be1ad2fe99d40074, 82656e8daf8de00935ae91b91bed43f4d6e0d644, 0e4f43779d550e559be13a5cdb763bad92c4cc99, e1c9866173c5f8521f2d0768547a01508cb9ff27 |
| Linux | Linux Kernel | 6.8 up to, but not including, 6.12.80; 6.13 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 7.0 | 6.12.80, 6.18.21, 6.19.11 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:N/AC:L/PR:N/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: dmaengine: idxd: fix possible wrong descriptor completion in llist_abort_desc() At the end of this function, d is the traversal cursor of flist, but the code completes found instead. This can lead to issues such as NULL pointer dereferences, double completion, or descriptor leaks. Fix this by completing d instead of found in the final list_for_each_entry_safe() loop.
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent NULL Pointer Dereference vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
- 8.2 High severity
- 7.5 High severity
- 7.5 High severity
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