VulnerabilityPublished 28 Oct 2026

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

Affects Linux kernelSource CVE Database V5

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

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · 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.

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–

Description

In the Linux kernel, the following vulnerability has been resolved: s390/pai: Handle multiple PMU stop callback invocations Handle the following scenario: The kernel protects itself against a very high sampling load and throttles the sampling using: perf_event_throttle() --> PMU->stop() Shortly later the scheduler may terminate the task and removes it from the CPU. It again calls PMU->stop() which results in two invocations of PMU->stop() called back to back. Protect against this and check the PERF_HES_STOPPED bit on function entry. If it is already set return. Clear bit PERF_HES_STOPPED in PMU->start(). Prohibit ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call for this event. It sets perf_event::event_limit to a positive value and causes perf_event_overflow() to invoke pai_stop() call back function when perf_event::event_limit hits zero. This is not supported because the sample events CRYPTO_ALL and NNPA_ALL are only taken at schedule out of a task. Use list_for_each_entry_safe() for safe iteration over syswide_list in pai_have_samples().

References

Community reviews

Loading reviews…