Linux: Use After Free
CVE-2026-63927 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 d5fc183ed614aeba6779cc992325be560f9a4451, 63b0dafa676aad4d0c3f01a61ad8e2990907660c, 9fe1d84f7e2cf33634e8afb7f4b7f8de182dd913 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 0.16% 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 d5fc183ed614aeba6779cc992325be560f9a4451 or 63b0dafa676aad4d0c3f01a61ad8e2990907660c or 9fe1d84f7e2cf33634e8afb7f4b7f8de182dd913 or 0584af4fe40fa5e254a05d69ce658746de641708, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, d5fc183ed614aeba6779cc992325be560f9a4451; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 63b0dafa676aad4d0c3f01a61ad8e2990907660c; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 9fe1d84f7e2cf33634e8afb7f4b7f8de182dd913; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 0584af4fe40fa5e254a05d69ce658746de641708; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, a15eeeceb94cbc04edef395e4d777ff554bdc27d; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 84ea928ed584756e59c6ac09736f12d1db95ded0; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 6d0b79d1d1118145e48a68192b6d733e39387053; 7359d482eb4d3967cc8be354405ae6be6eaf732c up to, but not including, 9ea06a3fbf9f16e0d98c52cb3b99642be15ec281; and 1 more ranges | d5fc183ed614aeba6779cc992325be560f9a4451, 63b0dafa676aad4d0c3f01a61ad8e2990907660c, 9fe1d84f7e2cf33634e8afb7f4b7f8de182dd913, 0584af4fe40fa5e254a05d69ce658746de641708, a15eeeceb94cbc04edef395e4d777ff554bdc27d, 84ea928ed584756e59c6ac09736f12d1db95ded0 |
| Linux | Linux Kernel | 3.10 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35 |
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: usb: dwc2: Fix use after free in debug code We're not allowed to dereference "urb" after calling usb_hcd_giveback_urb() so save the urb->status ahead of time.
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/0584af4fe40fa5e254a05d69ce658746de641708
- git.kernel.org/stable/c/63b0dafa676aad4d0c3f01a61ad8e2990907660c
- git.kernel.org/stable/c/6d0b79d1d1118145e48a68192b6d733e39387053
- git.kernel.org/stable/c/84ea928ed584756e59c6ac09736f12d1db95ded0
- git.kernel.org/stable/c/9ea06a3fbf9f16e0d98c52cb3b99642be15ec281
- git.kernel.org/stable/c/9fe1d84f7e2cf33634e8afb7f4b7f8de182dd913
- git.kernel.org/stable/c/a15eeeceb94cbc04edef395e4d777ff554bdc27d
- git.kernel.org/stable/c/d5fc183ed614aeba6779cc992325be560f9a4451
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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