CVE-2026-72236: Linux kernel · s390/perf_cpum_cf: Add missing array_index_nospec() to __hw_perf_event_init()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.7 Medium · fixed in 6.8.0-147.147 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-147.147, 6.8.0-1067.70, 7.0.0-1014.14~24.04.1 +25
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available and should be applied to affected Linux kernel versions. Users should update their systems to the fixed kernel releases. No additional mitigation is required as the patch fully addresses the issue.
Description
A vulnerability in the Linux kernel's s390 architecture perf_cpum_cf subsystem was resolved by adding a missing speculation barrier (array_index_nospec) to the __hw_perf_event_init() function. The flaw involved a userspace-controlled variable used as an array index without proper speculative execution mitigation, potentially allowing speculative execution side-channel attacks. This issue affects specific Linux kernel versions and has been fixed in updated releases. The vulnerability is rated medium severity and no known exploits are reported in the wild.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72236 (opens in a new tab)
- git.kernel.org/stable/c/27206bb57c47bdbe33bccc78fa7f7e2a719a06b9 (opens in a new tab)
- git.kernel.org/stable/c/49145bce539117db4b6e9e83c0e5ef528e361050 (opens in a new tab)
- git.kernel.org/stable/c/a21f3615c88421df81060b6ff89220fd34094c4d (opens in a new tab)
- git.kernel.org/stable/c/f79dff8c721bbb1f3fc312ea55e0551c2cc28801 (opens in a new tab)
- git.kernel.org/stable/c/fa1ebae4206e6afc8caa642e9eb1bbe39a9a724f (opens in a new tab)
- ubuntu.com/security/CVE-2026-72236 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72236 (opens in a new tab)
- git.kernel.org/linus/49145bce539117db4b6e9e83c0e5ef528e361050 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8917-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8918-1 (opens in a new tab)