Linux: Double Free
CVE-2026-31730 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 4b8e527aca357a6488680713bd88007cf8f547fe, 0bdee4118340c5a756220c1b29a7dab86bb0aa65, 3a164f640953cc982804746e772d379171aff5c6 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 4b8e527aca357a6488680713bd88007cf8f547fe or 0bdee4118340c5a756220c1b29a7dab86bb0aa65 or 3a164f640953cc982804746e772d379171aff5c6 or f67d368d26764a357691b2b3a33d3cb55b435bfc, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.134 or 6.12.81 or 6.18.22 or 6.19.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0871561055e666da421d779397efcc1e5e964cab up to, but not including, 4b8e527aca357a6488680713bd88007cf8f547fe; 0871561055e666da421d779397efcc1e5e964cab up to, but not including, 0bdee4118340c5a756220c1b29a7dab86bb0aa65; 0871561055e666da421d779397efcc1e5e964cab up to, but not including, 3a164f640953cc982804746e772d379171aff5c6; 0871561055e666da421d779397efcc1e5e964cab up to, but not including, f67d368d26764a357691b2b3a33d3cb55b435bfc; 0871561055e666da421d779397efcc1e5e964cab up to, but not including, ba2c83167b215da30fa2aae56b140198cf8d8408; 6.2 | 4b8e527aca357a6488680713bd88007cf8f547fe, 0bdee4118340c5a756220c1b29a7dab86bb0aa65, 3a164f640953cc982804746e772d379171aff5c6, f67d368d26764a357691b2b3a33d3cb55b435bfc, ba2c83167b215da30fa2aae56b140198cf8d8408 |
| Linux | Linux Kernel | 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 | 6.6.134, 6.12.81, 6.18.22, 6.19.12 |
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: misc: fastrpc: possible double-free of cctx->remote_heap fastrpc_init_create_static_process() may free cctx->remote_heap on the err_map path but does not clear the pointer. Later, fastrpc_rpmsg_remove() frees cctx->remote_heap again if it is non-NULL, which can lead to a double-free if the INIT_CREATE_STATIC ioctl hits the error path and the rpmsg device is subsequently removed/unbound. Clear cctx->remote_heap after freeing it in the error path to prevent the later cleanup from freeing it again. This issue was found by an in-house analysis workflow that extracts AST-based information and runs static checks, with LLM assistance for triage, and was confirmed by manual code review. No hardware testing was performed.
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
- git.kernel.org/stable/c/0bdee4118340c5a756220c1b29a7dab86bb0aa65
- git.kernel.org/stable/c/3a164f640953cc982804746e772d379171aff5c6
- git.kernel.org/stable/c/4b8e527aca357a6488680713bd88007cf8f547fe
- git.kernel.org/stable/c/ba2c83167b215da30fa2aae56b140198cf8d8408
- git.kernel.org/stable/c/f67d368d26764a357691b2b3a33d3cb55b435bfc
Recent Double Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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