Linux: Use After Free
CVE-2025-71082 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 fff9206b0907252a41eb12b7c1407b9347df18b1, cca0e9206e3bcc63cd3e72193e60149165d493cc, c0ecb3e4451fe94f4315e6d09c4046dfbc42090b 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 0.14% 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 fff9206b0907252a41eb12b7c1407b9347df18b1 or cca0e9206e3bcc63cd3e72193e60149165d493cc or c0ecb3e4451fe94f4315e6d09c4046dfbc42090b or 1e54c19eaf84ba652c4e376571093e58e144b339, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.198 or 6.1.160 or 6.6.120 or 6.12.64, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, fff9206b0907252a41eb12b7c1407b9347df18b1; 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, cca0e9206e3bcc63cd3e72193e60149165d493cc; 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, c0ecb3e4451fe94f4315e6d09c4046dfbc42090b; 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, 1e54c19eaf84ba652c4e376571093e58e144b339; 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, fdf7c640fb8a44a59b0671143d8c2f738bc48003; 98921dbd00c4e2e4bdd56423cb5edf98d57b45f7 up to, but not including, 252714f1e8bdd542025b16321c790458014d6880; 3.7 | fff9206b0907252a41eb12b7c1407b9347df18b1, cca0e9206e3bcc63cd3e72193e60149165d493cc, c0ecb3e4451fe94f4315e6d09c4046dfbc42090b, 1e54c19eaf84ba652c4e376571093e58e144b339, fdf7c640fb8a44a59b0671143d8c2f738bc48003, 252714f1e8bdd542025b16321c790458014d6880 |
| Linux | Linux Kernel | 3.7.1 up to, but not including, 5.15.198; 5.16 up to, but not including, 6.1.160; 6.2 up to, but not including, 6.6.120; 6.7 up to, but not including, 6.12.64; 6.13 up to, but not including, 6.18.4; 3.7; 6.19 | 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.4 |
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: Bluetooth: btusb: revert use of devm_kzalloc in btusb This reverts commit 98921dbd00c4e ("Bluetooth: Use devm_kzalloc in btusb.c file"). In btusb_probe(), we use devm_kzalloc() to allocate the btusb data. This ties the lifetime of all the btusb data to the binding of a driver to one interface, INTF. In a driver that binds to other interfaces, ISOC and DIAG, this is an accident waiting to happen. The issue is revealed in btusb_disconnect(), where calling usb_driver_release_interface(&btusb_driver, data->intf) will have devm free the data that is also being used by the other interfaces of the driver that may not be released yet. To fix this, revert the use of devm and go back to freeing memory explicitly.
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/1e54c19eaf84ba652c4e376571093e58e144b339
- git.kernel.org/stable/c/252714f1e8bdd542025b16321c790458014d6880
- git.kernel.org/stable/c/c0ecb3e4451fe94f4315e6d09c4046dfbc42090b
- git.kernel.org/stable/c/cca0e9206e3bcc63cd3e72193e60149165d493cc
- git.kernel.org/stable/c/fdf7c640fb8a44a59b0671143d8c2f738bc48003
- git.kernel.org/stable/c/fff9206b0907252a41eb12b7c1407b9347df18b1
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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