Linux: Use After Free
CVE-2026-31532 is a high-severity use after free 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 1de30576a6dfeaaa27ef91fa272e6b9240b6fbd3, 64c8553decf5a5f2417bd54761ea0a832c56c4ca, 3f43f12fde34737fba091b7e3ab391e14ddbb0be 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 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 1de30576a6dfeaaa27ef91fa272e6b9240b6fbd3 or 64c8553decf5a5f2417bd54761ea0a832c56c4ca or 3f43f12fde34737fba091b7e3ab391e14ddbb0be or 5e9cfffad898bbeaafd0ea608a6d267362f050fc, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.83 or 6.18.24 or 6.19.14 or 7.0.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 1de30576a6dfeaaa27ef91fa272e6b9240b6fbd3; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 64c8553decf5a5f2417bd54761ea0a832c56c4ca; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 3f43f12fde34737fba091b7e3ab391e14ddbb0be; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 5e9cfffad898bbeaafd0ea608a6d267362f050fc; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 572f0bf536ebc14f6e7da3d21a85cf076de8358e; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 1a0f2de81f7fbdc538fc72d7d74609b79bc83cc0; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 7201a531b9a5ed892bfda5ded9194ef622de8ffa; 514ac99c64b22d83b52dfee3b8becaa69a92bc4a up to, but not including, 34c1741254ff972e8375faf176678a248826fe3a; and 2 more ranges | 1de30576a6dfeaaa27ef91fa272e6b9240b6fbd3, 64c8553decf5a5f2417bd54761ea0a832c56c4ca, 3f43f12fde34737fba091b7e3ab391e14ddbb0be, 5e9cfffad898bbeaafd0ea608a6d267362f050fc, 572f0bf536ebc14f6e7da3d21a85cf076de8358e, 1a0f2de81f7fbdc538fc72d7d74609b79bc83cc0 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 4.1 through 6.6.136; 6.7 up to, but not including, 6.12.83; 6.18 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 7.0 up to, but not including, 7.0.1 | 6.12.83, 6.18.24, 6.19.14, 7.0.1 |
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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: can: raw: fix ro->uniq use-after-free in raw_rcv() raw_release() unregisters raw CAN receive filters via can_rx_unregister(), but receiver deletion is deferred with call_rcu(). This leaves a window where raw_rcv() may still be running in an RCU read-side critical section after raw_release() frees ro->uniq, leading to a use-after-free of the percpu uniq storage. Move free_percpu(ro->uniq) out of raw_release() and into a raw-specific socket destructor. can_rx_unregister() takes an extra reference to the socket and only drops it from the RCU callback, so freeing uniq from sk_destruct ensures the percpu area is not released until the relevant callbacks have drained. [mkl: applied manually]
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1a0f2de81f7fbdc538fc72d7d74609b79bc83cc0
- git.kernel.org/stable/c/34c1741254ff972e8375faf176678a248826fe3a
- git.kernel.org/stable/c/572f0bf536ebc14f6e7da3d21a85cf076de8358e
- git.kernel.org/stable/c/5e9cfffad898bbeaafd0ea608a6d267362f050fc
- git.kernel.org/stable/c/7201a531b9a5ed892bfda5ded9194ef622de8ffa
- git.kernel.org/stable/c/a535a9217ca3f2fccedaafb2fddb4c48f27d36dc
Other references
Recent Use After Free vulnerabilities
- 9.6 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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