Linux: Use After Free
CVE-2026-43056 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 d88541ffd56d62a61e77209080001eddd4d69815, 43f5b19fd190fea20d052bc84741b28031d5baa9, 5f4061f8225d18695e5afe9bbf1cb7bd673d7872 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 d88541ffd56d62a61e77209080001eddd4d69815 or 43f5b19fd190fea20d052bc84741b28031d5baa9 or 5f4061f8225d18695e5afe9bbf1cb7bd673d7872 or e5a75bf026c686b91a7dc6f9c5caf5016745d1fe, 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 | a69839d4327d053b18d8e1b0e7ddeee78db78f4f up to, but not including, d88541ffd56d62a61e77209080001eddd4d69815; a69839d4327d053b18d8e1b0e7ddeee78db78f4f up to, but not including, 43f5b19fd190fea20d052bc84741b28031d5baa9; a69839d4327d053b18d8e1b0e7ddeee78db78f4f up to, but not including, 5f4061f8225d18695e5afe9bbf1cb7bd673d7872; a69839d4327d053b18d8e1b0e7ddeee78db78f4f up to, but not including, e5a75bf026c686b91a7dc6f9c5caf5016745d1fe; a69839d4327d053b18d8e1b0e7ddeee78db78f4f up to, but not including, c4ea7d8907cf72b259bf70bd8c2e791e1c4ff70f; 6.2 | d88541ffd56d62a61e77209080001eddd4d69815, 43f5b19fd190fea20d052bc84741b28031d5baa9, 5f4061f8225d18695e5afe9bbf1cb7bd673d7872, e5a75bf026c686b91a7dc6f9c5caf5016745d1fe, c4ea7d8907cf72b259bf70bd8c2e791e1c4ff70f |
| 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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: net: mana: fix use-after-free in add_adev() error path If auxiliary_device_add() fails, add_adev() jumps to add_fail and calls auxiliary_device_uninit(adev). The auxiliary device has its release callback set to adev_release(), which frees the containing struct mana_adev. Since adev is embedded in struct mana_adev, the subsequent fall-through to init_fail and access to adev->id may result in a use-after-free. Fix this by saving the allocated auxiliary device id in a local variable before calling auxiliary_device_add(), and use that saved id in the cleanup path after auxiliary_device_uninit().
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/43f5b19fd190fea20d052bc84741b28031d5baa9
- git.kernel.org/stable/c/5f4061f8225d18695e5afe9bbf1cb7bd673d7872
- git.kernel.org/stable/c/c4ea7d8907cf72b259bf70bd8c2e791e1c4ff70f
- git.kernel.org/stable/c/d88541ffd56d62a61e77209080001eddd4d69815
- git.kernel.org/stable/c/e5a75bf026c686b91a7dc6f9c5caf5016745d1fe
Recent Use After Free vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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