VulnerabilityPublished 23 Oct 2026

CVE-2026-98937: Linux kernel · perf/core: Check kernel access when kernel callchains are requested

Source GCVE Database

Authoritative record:CVE-2026-98937· Medium

Not known to be exploited · fixed in a4573a3838ae4fc73b70019cfa1dac9aaea7cc2f : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in a4573a3838ae4fc73b70019cfa1dac9aaea7cc2f, 2581b43e162cfc43e6f5d8dd8d2b38f3441550de, 132bee76097be421ab3012130b5b506324cf2be1 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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-5cg4-h7ff-5xr5

What to do

Upgrade Linux kernel to a4573a3838ae4fc73b70019cfa1dac9aaea7cc2f, 2581b43e162cfc43e6f5d8dd8d2b38f3441550de, 132bee76097be421ab3012130b5b506324cf2be1 or 6e187281f978a2bff98ead6aa40f8ddc9a2c9afb.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 0764771dab80d7b84b9a271bee7f1b21a04a3f0c, < a4573a3838ae4fc73b70019cfa1dac9aaea7cc2f	Fixed in a4573a3838ae4fc73b70019cfa1dac9aaea7cc2f
LinuxLinux	Affected ≥ 0764771dab80d7b84b9a271bee7f1b21a04a3f0c, < 2581b43e162cfc43e6f5d8dd8d2b38f3441550de	Fixed in 2581b43e162cfc43e6f5d8dd8d2b38f3441550de
LinuxLinux	Affected ≥ 0764771dab80d7b84b9a271bee7f1b21a04a3f0c, < 132bee76097be421ab3012130b5b506324cf2be1	Fixed in 132bee76097be421ab3012130b5b506324cf2be1
LinuxLinux	Affected ≥ 0764771dab80d7b84b9a271bee7f1b21a04a3f0c, < 6e187281f978a2bff98ead6aa40f8ddc9a2c9afb	Fixed in 6e187281f978a2bff98ead6aa40f8ddc9a2c9afb
LinuxLinux	Affected =2.6.31	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: perf/core: Check kernel access when kernel callchains are requested perf_event_open() currently gates perf_allow_kernel() only on !attr.exclude_kernel. However, users can still request kernel callchain collection with attr.exclude_callchain_kernel == 0 even when attr.exclude_kernel == 1. That still requires kernel profiling privilege, but the existing check does not enforce it. Update the permission check to call perf_allow_kernel() when either kernel sampling is requested or kernel callchains are requested. This keeps permission checks aligned with requested data and prevents unprivileged use of kernel callchain capture.

References

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