CVE-2026-31483: Linux kernel · s390/syscalls: Add spectre boundary for syscall dispatch table
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in f8c444b918d639e1f9a621ee20fe481c1d10dfc4 : patch Linux kernel soon.
Data as of 5 Nov 2026, 22:21 UTC
Rated High by Threat Radar's AI analysis · 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 f8c444b918d639e1f9a621ee20fe481c1d10dfc4, 87776f02449e3bded95b2ccbd6b012e9ae64e6f3, 48b8814e25d073dd84daf990a879a820bad2bcbd +4
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
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AI-suggested
A patch is available and has been applied to the Linux kernel to add the Spectre boundary for the s390 syscall dispatch table. Users should update to the fixed kernel versions or apply the relevant patches to mitigate this vulnerability. Since this is a kernel-level fix, applying the official update is the recommended action.
Description
CVE-2026-31483 is a vulnerability in the Linux kernel affecting the s390 architecture's syscall dispatch table. The issue arises because the syscall number, controlled by userspace, lacks proper bounds checking using array_index_nospec(), which is intended to prevent speculative execution attacks such as Spectre. This flaw has been addressed by adding a Spectre boundary to the syscall dispatch table.
References
- git.kernel.org/stable/c/3c3b97064764899c39a0abbd35a6caa031e70333 (opens in a new tab)
- git.kernel.org/stable/c/1cb9c7bc9025c637564fabc7fcc3c9343949e310 (opens in a new tab)
- git.kernel.org/stable/c/7a5260fbc6e79a1595328ec5c6aa3f937504a1f0 (opens in a new tab)
- git.kernel.org/stable/c/f8c444b918d639e1f9a621ee20fe481c1d10dfc4 (opens in a new tab)
- git.kernel.org/stable/c/87776f02449e3bded95b2ccbd6b012e9ae64e6f3 (opens in a new tab)
- git.kernel.org/stable/c/4d05dd18d867d58c6952a3bc260d244899da7256 (opens in a new tab)
- git.kernel.org/stable/c/48b8814e25d073dd84daf990a879a820bad2bcbd (opens in a new tab)