CyberSecBulletin
CVE-2026-31576NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-31576 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 87b9685cca91ed715c39ba544715832d26a7f4b4, 131ec9046e1c8af101aebdaec4e8095e05f3312b, 67fd62e3efdc9dce01f76d95a745212f4feb38e6 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.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 87b9685cca91ed715c39ba544715832d26a7f4b4 or 131ec9046e1c8af101aebdaec4e8095e05f3312b or 67fd62e3efdc9dce01f76d95a745212f4feb38e6 or 45cbaf5c7cdc5386d86377f0daf94a17a007fed0, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 87b9685cca91ed715c39ba544715832d26a7f4b4; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 131ec9046e1c8af101aebdaec4e8095e05f3312b; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 67fd62e3efdc9dce01f76d95a745212f4feb38e6; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 45cbaf5c7cdc5386d86377f0daf94a17a007fed0; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 98a0a81ce78020c2522e0046f49d200de9778cb9; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 07e9e674b6146b1f6fc41b1f54b8968bf2802824; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, 2145c71a8044362e82e9923f001ba2aeb771b848; 8bc4a9ed85046c214458c9e82aea75d2f46cfffd up to, but not including, fcd1d70792a35c8a97414fe429f48311e41269c2; and 2 more ranges87b9685cca91ed715c39ba544715832d26a7f4b4, 131ec9046e1c8af101aebdaec4e8095e05f3312b, 67fd62e3efdc9dce01f76d95a745212f4feb38e6, 45cbaf5c7cdc5386d86377f0daf94a17a007fed0, 98a0a81ce78020c2522e0046f49d200de9778cb9, 07e9e674b6146b1f6fc41b1f54b8968bf2802824
LinuxLinux Kernelbefore 6.6.136; 6.7 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 7.0 up to, but not including, 7.0.16.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1

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.

Official description

In the Linux kernel, the following vulnerability has been resolved: media: hackrf: fix to not free memory after the device is registered in hackrf_probe() In hackrf driver, the following race condition occurs: ``` CPU0 CPU1 hackrf_probe() kzalloc(); // alloc hackrf_dev .... v4l2_device_register(); .... fd = sys_open("/path/to/dev"); // open hackrf fd .... v4l2_device_unregister(); .... kfree(); // free hackrf_dev .... sys_ioctl(fd, ...); v4l2_ioctl(); video_is_registered() // UAF!! .... sys_close(fd); v4l2_release() // UAF!! hackrf_video_release() kfree(); // DFB!! ``` When a V4L2 or video device is unregistered, the device node is removed so new open() calls are blocked. However, file descriptors that are already open-and any in-flight I/O-do not terminate immediately; they remain valid until the last reference is dropped and the driver's release() is invoked. Therefore, freeing device memory on the error path after hackrf_probe() has registered dev it will lead to a race to use-after-free vuln, since those already-open handles haven't been released yet. And since release() free memory too, race to use-after-free and double-free vuln occur. To prevent this, if device is registered from probe(), it should be modified to free memory only through release() rather than calling kfree() directly.

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.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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