CVE-2026-31482: Linux kernel · s390/entry: Scrub r12 register on kernel entry
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in a58d298a83a3a9b7ca99ded9d60a1e77231159ef : update Linux kernel when convenient.
Data as of 5 Nov 2026, 22:21 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-05.
- Patch
- Available – fixed in a58d298a83a3a9b7ca99ded9d60a1e77231159ef, 0738d395aab8fae3b5a3ad3fc640630c91693c27, 99a8b420f3f0e162eb9c9c9253929d4d23f9bd30 +2
Exploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A patch is available and has been applied in the Linux kernel. Users should update to the fixed versions identified by the commits a58d298a83a3a9b7ca99ded9d60a1e77231159ef, 0738d395aab8fae3b5a3ad3fc640630c91693c27, 99a8b420f3f0e162eb9c9c9253929d4d23f9bd30, 95c899cd791803a5bf7b73e5994fbbe1cc1a9c36, and 7f4e3233faa8470dd0627bc49b2809f2bfebd909. Since this is a Linux kernel vulnerability, applying the official kernel updates will remediate the issue.
Description
A vulnerability in the Linux kernel s390 architecture entry code was fixed by ensuring the r12 register is scrubbed on kernel entry. Previously, after a code change removed certain branch prediction macros and the loading of r12 with the current task pointer, the r12 register was not cleared as it should have been. This fix adds the missing instruction to clear r12, making register scrubbing consistent across all kernel entry points.
References
- git.kernel.org/stable/c/a58d298a83a3a9b7ca99ded9d60a1e77231159ef (opens in a new tab)
- git.kernel.org/stable/c/95c899cd791803a5bf7b73e5994fbbe1cc1a9c36 (opens in a new tab)
- git.kernel.org/stable/c/7f4e3233faa8470dd0627bc49b2809f2bfebd909 (opens in a new tab)
- git.kernel.org/stable/c/99a8b420f3f0e162eb9c9c9253929d4d23f9bd30 (opens in a new tab)
- git.kernel.org/stable/c/0738d395aab8fae3b5a3ad3fc640630c91693c27 (opens in a new tab)