CVE-2026-31482
Published: April 23, 2026Last modified: April 23, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: s390/entry: Scrub r12 register on kernel entry Before commit f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP"), all entry handlers loaded r12 with the current task pointer (lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That commit removed TIF_ISOLATE_BP, dropping both the branch prediction macros and the r12 load, but did not add r12 to the register clearing sequence. Add the missing xgr %r12,%r12 to make the register scrub consistent across all entry points.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.5 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-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/0738d395aab8fae3b5a3ad3fc640630c91693c27
- https://git.kernel.org/stable/c/7f4e3233faa8470dd0627bc49b2809f2bfebd909
- https://git.kernel.org/stable/c/95c899cd791803a5bf7b73e5994fbbe1cc1a9c36
- https://git.kernel.org/stable/c/99a8b420f3f0e162eb9c9c9253929d4d23f9bd30
- https://git.kernel.org/stable/c/a58d298a83a3a9b7ca99ded9d60a1e77231159ef