Linux: Double Free
CVE-2026-31475 is a high-severity double 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 d472d1a52985211b92883bb64bbe710b45980190, 1a82c3272626db9006f4c2cad3adf2916417aed6, fe757092d2329c397ecb32f2bf68a5b1c4bd9193 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 d472d1a52985211b92883bb64bbe710b45980190 or 1a82c3272626db9006f4c2cad3adf2916417aed6 or fe757092d2329c397ecb32f2bf68a5b1c4bd9193 or 6.15, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.15 or 6.18.21 or 6.19.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0ec6bd16705fe21d6429d6b8f7981eae2142bba8 up to, but not including, d472d1a52985211b92883bb64bbe710b45980190; 0ec6bd16705fe21d6429d6b8f7981eae2142bba8 up to, but not including, 1a82c3272626db9006f4c2cad3adf2916417aed6; 0ec6bd16705fe21d6429d6b8f7981eae2142bba8 up to, but not including, fe757092d2329c397ecb32f2bf68a5b1c4bd9193; f8434b8ba437d3f6cbcd9ffe8405bd16ed28fc5c; 6.14.9 up to, but not including, 6.15; 6.15 | d472d1a52985211b92883bb64bbe710b45980190, 1a82c3272626db9006f4c2cad3adf2916417aed6, fe757092d2329c397ecb32f2bf68a5b1c4bd9193, 6.15 |
| Linux | Linux Kernel | 6.14.9 up to, but not including, 6.15; 6.15.1 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 6.15; 7.0 | 6.15, 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
- 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: ASoC: sma1307: fix double free of devm_kzalloc() memory A previous change added NULL checks and cleanup for allocation failures in sma1307_setting_loaded(). However, the cleanup for mode_set entries is wrong. Those entries are allocated with devm_kzalloc(), so they are device-managed resources and must not be freed with kfree(). Manually freeing them in the error path can lead to a double free when devres later releases the same memory. Drop the manual kfree() loop and let devres handle the cleanup.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Double Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
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