Linux: Use After Free
CVE-2023-53479 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 748fadc08bcbdaf573b34d9784bb3dbd87441dbf, 316db489647b8ddc381682597e89787eac61a278, 4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe 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 748fadc08bcbdaf573b34d9784bb3dbd87441dbf or 316db489647b8ddc381682597e89787eac61a278 or 4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.43 or 6.4.8, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e50fe01e1f2a4aba2275edee7d5c77ac87674ddb up to, but not including, 748fadc08bcbdaf573b34d9784bb3dbd87441dbf; e50fe01e1f2a4aba2275edee7d5c77ac87674ddb up to, but not including, 316db489647b8ddc381682597e89787eac61a278; e50fe01e1f2a4aba2275edee7d5c77ac87674ddb up to, but not including, 4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe; 6.0 | 748fadc08bcbdaf573b34d9784bb3dbd87441dbf, 316db489647b8ddc381682597e89787eac61a278, 4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.1.43; 6.2 up to, but not including, 6.4.8; 6.5 | 6.1.43, 6.4.8 |
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: cxl/acpi: Fix a use-after-free in cxl_parse_cfmws() KASAN and KFENCE detected an user-after-free in the CXL driver. This happens in the cxl_decoder_add() fail path. KASAN prints the following error: BUG: KASAN: slab-use-after-free in cxl_parse_cfmws (drivers/cxl/acpi.c:299) This happens in cxl_parse_cfmws(), where put_device() is called, releasing cxld, which is accessed later. Use the local variables in the dev_err() instead of pointing to the released memory. Since the dev_err() is printing a resource, change the open coded print format to use the %pr format specifier.
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
Recent Use After Free vulnerabilities
- 8.1 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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