Linux: Double Free
CVE-2026-43120 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 62298a48f8b8788ad8b8464e6ffdf1ddebd2217e, 66964118f1f50ed85001c8fc9f7ab5bbdd021ee0, 0f22c32141acdcda266b26cab2b830baf870f3e0 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 62298a48f8b8788ad8b8464e6ffdf1ddebd2217e or 66964118f1f50ed85001c8fc9f7ab5bbdd021ee0 or 0f22c32141acdcda266b26cab2b830baf870f3e0 or 0c5d70bcb9d2275a1c8515a924016fcfeb4ab441, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 715fdb3b30541cc8180b7cdc6aa9f8c307afdf25 up to, but not including, 62298a48f8b8788ad8b8464e6ffdf1ddebd2217e; 5ac388db27c443dadfbb0b8b23fa7ccf429d901a up to, but not including, 66964118f1f50ed85001c8fc9f7ab5bbdd021ee0; 5ac388db27c443dadfbb0b8b23fa7ccf429d901a up to, but not including, 0f22c32141acdcda266b26cab2b830baf870f3e0; 5ac388db27c443dadfbb0b8b23fa7ccf429d901a up to, but not including, 0c5d70bcb9d2275a1c8515a924016fcfeb4ab441; 5ac388db27c443dadfbb0b8b23fa7ccf429d901a up to, but not including, 29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2; 6.6.120 up to, but not including, 6.6.136; 6.7 | 62298a48f8b8788ad8b8464e6ffdf1ddebd2217e, 66964118f1f50ed85001c8fc9f7ab5bbdd021ee0, 0f22c32141acdcda266b26cab2b830baf870f3e0, 0c5d70bcb9d2275a1c8515a924016fcfeb4ab441, 29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2, 6.6.136 |
| Linux | Linux Kernel | 6.6.120 up to, but not including, 6.6.136; 6.7 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 7.0 | 6.6.136, 6.12.83, 6.18.24, 6.19.14 |
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: RDMA/irdma: Fix double free related to rereg_user_mr If IB_MR_REREG_TRANS is set during rereg_user_mr, the umem will be released and a new one will be allocated in irdma_rereg_mr_trans. If any step of irdma_rereg_mr_trans fails after the new umem is allocated, it releases the umem, but does not set iwmr->region to NULL. The problem is that this failure is propagated to the user, who will then call ibv_dereg_mr (as they should). Then, the dereg_mr path will see a non-NULL umem and attempt to call ib_umem_release again. Fix this by setting iwmr->region to NULL after ib_umem_release. Fixed: 5ac388db27c4 ("RDMA/irdma: Add support to re-register a memory region")
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.
- 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/0c5d70bcb9d2275a1c8515a924016fcfeb4ab441
- git.kernel.org/stable/c/0f22c32141acdcda266b26cab2b830baf870f3e0
- git.kernel.org/stable/c/29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2
- git.kernel.org/stable/c/62298a48f8b8788ad8b8464e6ffdf1ddebd2217e
- git.kernel.org/stable/c/66964118f1f50ed85001c8fc9f7ab5bbdd021ee0
Recent Double Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.