Linux: Use After Free
CVE-2026-43458 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 23a3ac2e2262a291498567418227b99e1f3606b1, 52135420e9f75853ea0c6cea7b736e3e98495f7d, ca2ceba983bb23ea0202c2882d963253416654a3 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 0.12% 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 23a3ac2e2262a291498567418227b99e1f3606b1 or 52135420e9f75853ea0c6cea7b736e3e98495f7d or ca2ceba983bb23ea0202c2882d963253416654a3 or 8460187b4852fd00bd1c76394358053f3fa4d089, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.167 or 6.6.130, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 23a3ac2e2262a291498567418227b99e1f3606b1; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 52135420e9f75853ea0c6cea7b736e3e98495f7d; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, ca2ceba983bb23ea0202c2882d963253416654a3; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 8460187b4852fd00bd1c76394358053f3fa4d089; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 27e43356d0defb9fc7fa25265219a3ffeb7b3e98; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 35b58d3bc716ebb9ebd10fe1cac8c1177242511c; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 97a0bb491cae39478c6225381f14e9ac67b7bba7; e31d5a05948e4478ba8396063d1e1f39880928e2 up to, but not including, 288598d80a068a0e9281de35bcb4ce495f189e2a; and 1 more ranges | 23a3ac2e2262a291498567418227b99e1f3606b1, 52135420e9f75853ea0c6cea7b736e3e98495f7d, ca2ceba983bb23ea0202c2882d963253416654a3, 8460187b4852fd00bd1c76394358053f3fa4d089, 27e43356d0defb9fc7fa25265219a3ffeb7b3e98, 35b58d3bc716ebb9ebd10fe1cac8c1177242511c |
| Linux | Linux Kernel | 2.6.35 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.19; 6.19 up to, but not including, 6.19.9; 7.0 | 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.19 |
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: serial: caif: hold tty->link reference in ldisc_open and ser_release A reproducer triggers a KASAN slab-use-after-free in pty_write_room() when caif_serial's TX path calls tty_write_room(). The faulting access is on tty->link->port. Hold an extra kref on tty->link for the lifetime of the caif_serial line discipline: get it in ldisc_open() and drop it in ser_release(), and also drop it on the ldisc_open() error path. With this change applied, the reproducer no longer triggers the UAF in my testing.
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/23a3ac2e2262a291498567418227b99e1f3606b1
- git.kernel.org/stable/c/27e43356d0defb9fc7fa25265219a3ffeb7b3e98
- git.kernel.org/stable/c/288598d80a068a0e9281de35bcb4ce495f189e2a
- git.kernel.org/stable/c/35b58d3bc716ebb9ebd10fe1cac8c1177242511c
- git.kernel.org/stable/c/52135420e9f75853ea0c6cea7b736e3e98495f7d
- git.kernel.org/stable/c/8460187b4852fd00bd1c76394358053f3fa4d089
- git.kernel.org/stable/c/97a0bb491cae39478c6225381f14e9ac67b7bba7
- git.kernel.org/stable/c/ca2ceba983bb23ea0202c2882d963253416654a3
Recent Use After Free vulnerabilities
- 7.3 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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