Linux: Use After Free
CVE-2024-49874 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 56bddf543d4d7ddeff3f87b554ddacfdf086bffe, 4ac637122930cc4ab7e2c22e364cf3aaf96b05b1, 4318998892bf8fe99f97bea18c37ae7b685af75a 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 56bddf543d4d7ddeff3f87b554ddacfdf086bffe or 4ac637122930cc4ab7e2c22e364cf3aaf96b05b1 or 4318998892bf8fe99f97bea18c37ae7b685af75a or 27b55724d3f781dd6e635e89dc6e2fd78fa81a00, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.55 or 6.10.14 or 6.11.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 87e0f28eda36c7843523aa8dd0c5dab3331e9718 up to, but not including, 56bddf543d4d7ddeff3f87b554ddacfdf086bffe; 0f74f8b6675cc36d689abb4d9b3d75ab4049b7d7 up to, but not including, 4ac637122930cc4ab7e2c22e364cf3aaf96b05b1; 0f74f8b6675cc36d689abb4d9b3d75ab4049b7d7 up to, but not including, 4318998892bf8fe99f97bea18c37ae7b685af75a; 0f74f8b6675cc36d689abb4d9b3d75ab4049b7d7 up to, but not including, 27b55724d3f781dd6e635e89dc6e2fd78fa81a00; 0f74f8b6675cc36d689abb4d9b3d75ab4049b7d7 up to, but not including, 61850725779709369c7e907ae8c7c75dc7cec4f3; 6.4 | 56bddf543d4d7ddeff3f87b554ddacfdf086bffe, 4ac637122930cc4ab7e2c22e364cf3aaf96b05b1, 4318998892bf8fe99f97bea18c37ae7b685af75a, 27b55724d3f781dd6e635e89dc6e2fd78fa81a00, 61850725779709369c7e907ae8c7c75dc7cec4f3 |
| Linux | Linux Kernel | 6.4 up to, but not including, 6.6.55; 6.7 up to, but not including, 6.10.14; 6.11 up to, but not including, 6.11.3 | 6.6.55, 6.10.14, 6.11.3 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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 | 7.0 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: Fix use after free vulnerability in svc_i3c_master Driver Due to Race Condition In the svc_i3c_master_probe function, &master->hj_work is bound with svc_i3c_master_hj_work, &master->ibi_work is bound with svc_i3c_master_ibi_work. And svc_i3c_master_ibi_work can start the hj_work, svc_i3c_master_irq_handler can start the ibi_work. If we remove the module which will call svc_i3c_master_remove to make cleanup, it will free master->base through i3c_master_unregister while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | svc_i3c_master_hj_work svc_i3c_master_remove | i3c_master_unregister(&master->base)| device_unregister(&master->dev) | device_release | //free master->base | | i3c_master_do_daa(&master->base) | //use master->base Fix it by ensuring that the work is canceled before proceeding with the cleanup in svc_i3c_master_remove.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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