Linux: NULL Pointer Dereference
CVE-2026-43117 is a critical-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 9.1 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 4a7bab35fad5251c8cb738161152578cd83b6b9c, 520e8b4bcf872a534a7bf61ccf880047642df296, e252db8ca2a01f82d472091f35d549b313278636 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 4a7bab35fad5251c8cb738161152578cd83b6b9c or 520e8b4bcf872a534a7bf61ccf880047642df296 or e252db8ca2a01f82d472091f35d549b313278636 or c09a7446aab5773f38d6abb25fce99b8e1dfbc97, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, 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 | bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, 4a7bab35fad5251c8cb738161152578cd83b6b9c; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, 520e8b4bcf872a534a7bf61ccf880047642df296; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, e252db8ca2a01f82d472091f35d549b313278636; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, c09a7446aab5773f38d6abb25fce99b8e1dfbc97; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, 32372781d664a9b03c40343e96c29d0a6139f97d; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, 2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, d110d7cdb045715c0b45b0dfd974525bb38f653d; bc074524e123ded281cde25ebc5661910f9679e3 up to, but not including, a85b46db143fda5869e7d8df8f258ccef5fa1719; and 1 more ranges | 4a7bab35fad5251c8cb738161152578cd83b6b9c, 520e8b4bcf872a534a7bf61ccf880047642df296, e252db8ca2a01f82d472091f35d549b313278636, c09a7446aab5773f38d6abb25fce99b8e1dfbc97, 32372781d664a9b03c40343e96c29d0a6139f97d, 2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 4.8 up to, but not including, 6.6.136; 6.7 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 7.0 | 6.6.136, 6.12.83, 6.18.24, 6.19.14 |
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
- NoneNothing can be modified.
- 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:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file() If overlay is used on top of btrfs, dentry->d_sb translates to overlay's super block and fsid assignment will lead to a crash. Use file_inode(file)->i_sb to always get btrfs_sb.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a
- git.kernel.org/stable/c/32372781d664a9b03c40343e96c29d0a6139f97d
- git.kernel.org/stable/c/a85b46db143fda5869e7d8df8f258ccef5fa1719
- git.kernel.org/stable/c/c09a7446aab5773f38d6abb25fce99b8e1dfbc97
- git.kernel.org/stable/c/d110d7cdb045715c0b45b0dfd974525bb38f653d
Other references
Recent NULL Pointer Dereference vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
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