CVE-2026-43458
Published: May 21, 2026Last modified: May 21, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.8 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.167-r0) |
| 25 LTS | linux-lts | Fixed (6.12.80-r0) | |
| Stream | linux-lts | Fixed (6.12.80-r0) |
References
- https://git.kernel.org/stable/c/23a3ac2e2262a291498567418227b99e1f3606b1
- https://git.kernel.org/stable/c/27e43356d0defb9fc7fa25265219a3ffeb7b3e98
- https://git.kernel.org/stable/c/288598d80a068a0e9281de35bcb4ce495f189e2a
- https://git.kernel.org/stable/c/35b58d3bc716ebb9ebd10fe1cac8c1177242511c
- https://git.kernel.org/stable/c/52135420e9f75853ea0c6cea7b736e3e98495f7d
- https://git.kernel.org/stable/c/8460187b4852fd00bd1c76394358053f3fa4d089
- https://git.kernel.org/stable/c/97a0bb491cae39478c6225381f14e9ac67b7bba7
- https://git.kernel.org/stable/c/ca2ceba983bb23ea0202c2882d963253416654a3