Linux: Use After Free
CVE-2026-46215 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 672464dd53231509c9c771110798c56d4660e19e, 61bd96d3e5472c253f9c1ab77608f0c8aaa9d025, 5e28b7b94408897e41c63477aabc9e1db439bc8c 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 0.23% 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 672464dd53231509c9c771110798c56d4660e19e or 61bd96d3e5472c253f9c1ab77608f0c8aaa9d025 or 5e28b7b94408897e41c63477aabc9e1db439bc8c, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.32 or 7.0.9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 53096728b8910c6916ecc6c46a5abc5c678b58d9 up to, but not including, 672464dd53231509c9c771110798c56d4660e19e; 53096728b8910c6916ecc6c46a5abc5c678b58d9 up to, but not including, 61bd96d3e5472c253f9c1ab77608f0c8aaa9d025; 53096728b8910c6916ecc6c46a5abc5c678b58d9 up to, but not including, 5e28b7b94408897e41c63477aabc9e1db439bc8c; 6.18 | 672464dd53231509c9c771110798c56d4660e19e, 61bd96d3e5472c253f9c1ab77608f0c8aaa9d025, 5e28b7b94408897e41c63477aabc9e1db439bc8c |
| Linux | Linux Kernel | 6.18 up to, but not including, 6.18.32; 6.19 up to, but not including, 7.0.9; 7.1 | 6.18.32, 7.0.9 |
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: drm: Set old handle to NULL before prime swap in change_handle There was a potential race condition in change_handle. The ioctl briefly had a single object with two idr entries; a concurrent gem_close could delete the object and remove one of the handles while leaving the other one dangling, which could subsequently be dereferenced for a use-after-free. To fix this, do the same dance that gem_close itself does. (f6cd7daecff5 drm: Release driver references to handle before making it available again) First idr_replace the old handle to NULL. Later, if the prime operations are successful, actually close it. create_tail required a similar dance to avoid a similar problem. (bd46cece51a3 drm/gem: Fix race in drm_gem_handle_create_tail()) It idr_allocs the new handle with NULL, then swaps in the correct object later to avoid races. We don't need to do that here, since the only operations that could race are drm_prime, and change_handle holds the prime lock for the entire duration. v2: cleanups of error paths
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: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
- 8.3 High severity
- 8.8 High severity
- 8.3 High severity
- 8.3 High severity
- 8.8 High severity
- 7.5 High severity
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