Linux: Use After Free
CVE-2022-49724 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 c4b0b8edccb0cfb15a8cecf4161e0571d3daac64, c83a1d40dc624070a203eb383ef9fb60eb634136, f7183c76d500324b8b5bd0af5e663cfa57b7b836 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 0.28% 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 c4b0b8edccb0cfb15a8cecf4161e0571d3daac64 or c83a1d40dc624070a203eb383ef9fb60eb634136 or f7183c76d500324b8b5bd0af5e663cfa57b7b836 or 65ca4db68b6819244df9024aea4be55edf8af1ef, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.285 or 4.19.249 or 5.4.200 or 5.10.124, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, c4b0b8edccb0cfb15a8cecf4161e0571d3daac64; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, c83a1d40dc624070a203eb383ef9fb60eb634136; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, f7183c76d500324b8b5bd0af5e663cfa57b7b836; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, 65ca4db68b6819244df9024aea4be55edf8af1ef; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, fb15e79cacddfbc62264e6e807bde50ad688e988; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, a6fcd7ffd76a9c1d998a2d02d518c78a55c5bed8; 465893e18878e119d8d0255439fad8debbd646fd up to, but not including, 499e13aac6c762e1e828172b0f0f5275651d6512; 4.6 | c4b0b8edccb0cfb15a8cecf4161e0571d3daac64, c83a1d40dc624070a203eb383ef9fb60eb634136, f7183c76d500324b8b5bd0af5e663cfa57b7b836, 65ca4db68b6819244df9024aea4be55edf8af1ef, fb15e79cacddfbc62264e6e807bde50ad688e988, a6fcd7ffd76a9c1d998a2d02d518c78a55c5bed8 |
| Linux | Linux Kernel | 4.6 up to, but not including, 4.14.285; 4.15 up to, but not including, 4.19.249; 4.20 up to, but not including, 5.4.200; 5.5 up to, but not including, 5.10.124; 5.11 up to, but not including, 5.15.49; 5.16 up to, but not including, 5.18.6; 5.19 | 4.14.285, 4.19.249, 5.4.200, 5.10.124, 5.15.49, 5.18.6 |
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: tty: goldfish: Fix free_irq() on remove Pass the correct dev_id to free_irq() to fix this splat when the driver is unbound: WARNING: CPU: 0 PID: 30 at kernel/irq/manage.c:1895 free_irq Trying to free already-free IRQ 65 Call Trace: warn_slowpath_fmt free_irq goldfish_tty_remove platform_remove device_remove device_release_driver_internal device_driver_detach unbind_store drv_attr_store ...
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/499e13aac6c762e1e828172b0f0f5275651d6512
- git.kernel.org/stable/c/65ca4db68b6819244df9024aea4be55edf8af1ef
- git.kernel.org/stable/c/a6fcd7ffd76a9c1d998a2d02d518c78a55c5bed8
- git.kernel.org/stable/c/c4b0b8edccb0cfb15a8cecf4161e0571d3daac64
- git.kernel.org/stable/c/c83a1d40dc624070a203eb383ef9fb60eb634136
- git.kernel.org/stable/c/f7183c76d500324b8b5bd0af5e663cfa57b7b836
- git.kernel.org/stable/c/fb15e79cacddfbc62264e6e807bde50ad688e988
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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