Linux: Use After Free
CVE-2026-31389 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 0e23f50086da7d0b183dfeac26021acfcdee086b, 6bbd385b30c7fb6c7ee0669e9ada91490938c051, afe27c1f43aa57530011f419be6ddf71306565d2 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 0.12% 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 0e23f50086da7d0b183dfeac26021acfcdee086b or 6bbd385b30c7fb6c7ee0669e9ada91490938c051 or afe27c1f43aa57530011f419be6ddf71306565d2 or 80f3e8cd2b4ad355b2ad2024cf423f6d183404f7, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.167 or 6.6.130 or 6.12.78 or 6.18.20, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, 0e23f50086da7d0b183dfeac26021acfcdee086b; 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, 6bbd385b30c7fb6c7ee0669e9ada91490938c051; 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, afe27c1f43aa57530011f419be6ddf71306565d2; 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, 80f3e8cd2b4ad355b2ad2024cf423f6d183404f7; 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, 23b51bad2eb8787aa74324cfccefb258515ae5ba; 6598b91b5ac32bc756d7c3000a31f775d4ead1c4 up to, but not including, 8634e05b08ead636e926022f4a98416e13440df9; 6.0 | 0e23f50086da7d0b183dfeac26021acfcdee086b, 6bbd385b30c7fb6c7ee0669e9ada91490938c051, afe27c1f43aa57530011f419be6ddf71306565d2, 80f3e8cd2b4ad355b2ad2024cf423f6d183404f7, 23b51bad2eb8787aa74324cfccefb258515ae5ba, 8634e05b08ead636e926022f4a98416e13440df9 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.20; 6.19 up to, but not including, 6.19.10; 7.0 | 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10 |
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: spi: fix use-after-free on controller registration failure Make sure to deregister from driver core also in the unlikely event that per-cpu statistics allocation fails during controller registration to avoid use-after-free (of driver resources) and unclocked register accesses.
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/0e23f50086da7d0b183dfeac26021acfcdee086b
- git.kernel.org/stable/c/23b51bad2eb8787aa74324cfccefb258515ae5ba
- git.kernel.org/stable/c/6bbd385b30c7fb6c7ee0669e9ada91490938c051
- git.kernel.org/stable/c/80f3e8cd2b4ad355b2ad2024cf423f6d183404f7
- git.kernel.org/stable/c/8634e05b08ead636e926022f4a98416e13440df9
- git.kernel.org/stable/c/afe27c1f43aa57530011f419be6ddf71306565d2
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
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