Linux: Double Free
CVE-2026-43178 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 f9fe092084cd04deea18747f58a2304026e76aaa, 8adaff87db143583e08eec4f4e7788f1ef8af94d, 90f5e87c9b75833b9ef3a4415b92c0247f28ab2f 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 f9fe092084cd04deea18747f58a2304026e76aaa or 8adaff87db143583e08eec4f4e7788f1ef8af94d or 90f5e87c9b75833b9ef3a4415b92c0247f28ab2f or 61dc9f776705d6db6847c101b98fa4f0e9eb6fa3, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.75 or 6.18.16 or 6.19.6, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b9b97e6aeb534315f9646b2090d1a5024c6a4e82 up to, but not including, f9fe092084cd04deea18747f58a2304026e76aaa; cbc03ce3e6ce7e21214c3f02218213574c1a2d08 up to, but not including, 8adaff87db143583e08eec4f4e7788f1ef8af94d; b5cbacd7f86f4f62b8813688c8e73be94e8e1951 up to, but not including, 90f5e87c9b75833b9ef3a4415b92c0247f28ab2f; b5cbacd7f86f4f62b8813688c8e73be94e8e1951 up to, but not including, 61dc9f776705d6db6847c101b98fa4f0e9eb6fa3; 6.12.70 up to, but not including, 6.12.75; 6.18.10 up to, but not including, 6.18.16; 6.19 | f9fe092084cd04deea18747f58a2304026e76aaa, 8adaff87db143583e08eec4f4e7788f1ef8af94d, 90f5e87c9b75833b9ef3a4415b92c0247f28ab2f, 61dc9f776705d6db6847c101b98fa4f0e9eb6fa3, 6.12.75, 6.18.16 |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 6.12.70 up to, but not including, 6.12.75; 6.18.10 up to, but not including, 6.18.16; 6.19.1 up to, but not including, 6.19.6; 6.19 | 6.12.75, 6.18.16, 6.19.6 |
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 |
| CVSS 3.1 | 7.0 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: procfs: fix possible double mmput() in do_procmap_query() When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY we return with -ENAMETOOLONG error. After recent changes this condition happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(), so original goto out is now wrong and will double-mmput() mm_struct. Fix by jumping further to clean up only vm_file and name_buf.
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
Other references
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
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