CVE-2026-31482
s390/entry: Scrub r12 register on kernel entry
Summary
s390/entry: Scrub r12 register on kernel entry
Original description
The description as published by the source.
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.
Affected packages
Linux
Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"6.4.0"},{"fixed":"6.6.131"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.11"}]}]
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-31482 linux-lts Fixed in: 6.12.80-r0
- Debian DEBIAN-CVE-2026-31482 linux Fixed in: 6.12.85-1
- Ubuntu UBUNTU-CVE-2026-31482 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org