Linux: Use After Free
CVE-2026-31758 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 959ef329071136e4335b54822fe2f607659b4569, e189d443767f7cd390c52f2e122e1fc41c7562d6, 7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f 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 0.13% 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 959ef329071136e4335b54822fe2f607659b4569 or e189d443767f7cd390c52f2e122e1fc41c7562d6 or 7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f or 95e09b07e50290254b28b8395509473104518f8c, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.168 or 6.6.134, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, 959ef329071136e4335b54822fe2f607659b4569; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, e189d443767f7cd390c52f2e122e1fc41c7562d6; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, 7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, 95e09b07e50290254b28b8395509473104518f8c; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, d13318dec0c1e0e2ac16f8ecbd522db14cea4bb1; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, 977b632db51d231dec0bc571089a5c2402674139; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, d40198de50232e04c14c6e2092e896766c95ea48; 4f3c8d6eddc272b386464524235440a418ed2029 up to, but not including, 8a768552f7a8276fb9e01d49773d2094ace7c8f1; and 1 more ranges | 959ef329071136e4335b54822fe2f607659b4569, e189d443767f7cd390c52f2e122e1fc41c7562d6, 7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f, 95e09b07e50290254b28b8395509473104518f8c, d13318dec0c1e0e2ac16f8ecbd522db14cea4bb1, 977b632db51d231dec0bc571089a5c2402674139 |
| Linux | Linux Kernel | 4.19 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.134; 6.7 up to, but not including, 6.12.81; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.0 | 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22 |
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: usb: usbtmc: Flush anchored URBs in usbtmc_release When calling usbtmc_release, pending anchored URBs must be flushed or killed to prevent use-after-free errors (e.g. in the HCD giveback path). Call usbtmc_draw_down() to allow anchored URBs to be completed.
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/7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f
- git.kernel.org/stable/c/8a768552f7a8276fb9e01d49773d2094ace7c8f1
- git.kernel.org/stable/c/959ef329071136e4335b54822fe2f607659b4569
- git.kernel.org/stable/c/95e09b07e50290254b28b8395509473104518f8c
- git.kernel.org/stable/c/977b632db51d231dec0bc571089a5c2402674139
- git.kernel.org/stable/c/d13318dec0c1e0e2ac16f8ecbd522db14cea4bb1
- git.kernel.org/stable/c/d40198de50232e04c14c6e2092e896766c95ea48
- git.kernel.org/stable/c/e189d443767f7cd390c52f2e122e1fc41c7562d6
Recent Use After Free vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
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