VulnerabilityPublished 28 Oct 2026

CVE-2026-99125: Linux kernel · s390/pai: Handle multiple PMU stop callback invocations

Source GCVE Database

Authoritative record:CVE-2026-99125

Not known to be exploited : upgrade to f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40 or cf348ec613f75b9774291e47b804fd7010835a6c when convenient.

Data as of 28 Oct 2026, 14:13 UTC

Severity

Low

Rated Low by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40, cf348ec613f75b9774291e47b804fd7010835a6c

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-83qv-jr76-p4xc

What to do

Upgrade Linux kernel to f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40 or cf348ec613f75b9774291e47b804fd7010835a6c.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 9f66572f2889a5e72a9d7e17787e52f03b1f7bd8, < f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40	Fixed in f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40
LinuxLinux	Affected ≥ 9f66572f2889a5e72a9d7e17787e52f03b1f7bd8, < cf348ec613f75b9774291e47b804fd7010835a6c	Fixed in cf348ec613f75b9774291e47b804fd7010835a6c
LinuxLinux	Affected =6.11	Fixed in–

AI-suggested

A fix has been applied in the Linux kernel to handle multiple PMU stop callback invocations safely by checking the PERF_HES_STOPPED bit and prohibiting unsupported ioctl calls. Users should update to a Linux kernel version that includes this patch once available. Until then, avoid using the ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call with the affected events on s390 systems.

Description

A vulnerability in the Linux kernel's s390/pai subsystem involves improper handling of multiple invocations of the PMU stop callback. The kernel may call PMU->stop() twice consecutively due to task scheduling and throttling behavior, which was not properly protected against. The fix involves checking a status bit to prevent double processing and prohibiting certain ioctl calls that cause unsupported event limit behavior.

References

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