Linux: Use After Free
CVE-2025-21929 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 9c677fe859a73f5dd3dd84c27f99e10d28047c73, e040f11fbca868c6d151e9f2c5730c476abfcf17, 823987841424289339fdb4ba90e6d2c3792836db 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 9c677fe859a73f5dd3dd84c27f99e10d28047c73 or e040f11fbca868c6d151e9f2c5730c476abfcf17 or 823987841424289339fdb4ba90e6d2c3792836db, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.19 or 6.13.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f645a90e8ff732c48dd9f18815baef08c44ac8a0 up to, but not including, 9c677fe859a73f5dd3dd84c27f99e10d28047c73; f645a90e8ff732c48dd9f18815baef08c44ac8a0 up to, but not including, e040f11fbca868c6d151e9f2c5730c476abfcf17; f645a90e8ff732c48dd9f18815baef08c44ac8a0 up to, but not including, 823987841424289339fdb4ba90e6d2c3792836db; 6.8 | 9c677fe859a73f5dd3dd84c27f99e10d28047c73, e040f11fbca868c6d151e9f2c5730c476abfcf17, 823987841424289339fdb4ba90e6d2c3792836db |
| Linux | Linux Kernel | 6.8 up to, but not including, 6.12.19; 6.13 up to, but not including, 6.13.7; 6.14 | 6.12.19, 6.13.7 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: HID: intel-ish-hid: Fix use-after-free issue in hid_ishtp_cl_remove() During the `rmmod` operation for the `intel_ishtp_hid` driver, a use-after-free issue can occur in the hid_ishtp_cl_remove() function. The function hid_ishtp_cl_deinit() is called before ishtp_hid_remove(), which can lead to accessing freed memory or resources during the removal process. Call Trace: ? ishtp_cl_send+0x168/0x220 [intel_ishtp] ? hid_output_report+0xe3/0x150 [hid] hid_ishtp_set_feature+0xb5/0x120 [intel_ishtp_hid] ishtp_hid_request+0x7b/0xb0 [intel_ishtp_hid] hid_hw_request+0x1f/0x40 [hid] sensor_hub_set_feature+0x11f/0x190 [hid_sensor_hub] _hid_sensor_power_state+0x147/0x1e0 [hid_sensor_trigger] hid_sensor_runtime_resume+0x22/0x30 [hid_sensor_trigger] sensor_hub_remove+0xa8/0xe0 [hid_sensor_hub] hid_device_remove+0x49/0xb0 [hid] hid_destroy_device+0x6f/0x90 [hid] ishtp_hid_remove+0x42/0x70 [intel_ishtp_hid] hid_ishtp_cl_remove+0x6b/0xb0 [intel_ishtp_hid] ishtp_cl_device_remove+0x4a/0x60 [intel_ishtp] ... Additionally, ishtp_hid_remove() is a HID level power off, which should occur before the ISHTP level disconnect. This patch resolves the issue by reordering the calls in hid_ishtp_cl_remove(). The function ishtp_hid_remove() is now called before hid_ishtp_cl_deinit().
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
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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