VulnerabilityPublished 23 Oct 2026Updated 26 Oct 2026

CVE-2026-98942: Linux kernel · sched_ext: Build the cid tables privately and publish them with RCU

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to 3a773220d39ba993dfe5d135f8b610be10794d5d or 0e1a74369bdbc357d3d9713734418d914a981553 when convenient.

Data as of 26 Oct 2026, 14:18 UTC

Severity

Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3a773220d39ba993dfe5d135f8b610be10794d5d, 0e1a74369bdbc357d3d9713734418d914a981553

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.

What to do

Upgrade Linux kernel to 3a773220d39ba993dfe5d135f8b610be10794d5d or 0e1a74369bdbc357d3d9713734418d914a981553.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ e9b55af47edf6e60c9a47b5604c3e15c5162ec86, < 3a773220d39ba993dfe5d135f8b610be10794d5d	Fixed in 3a773220d39ba993dfe5d135f8b610be10794d5d
LinuxLinux	Affected ≥ e9b55af47edf6e60c9a47b5604c3e15c5162ec86, < 0e1a74369bdbc357d3d9713734418d914a981553	Fixed in 0e1a74369bdbc357d3d9713734418d914a981553
LinuxLinux	Affected =7.2	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel as indicated by the fixed commit versions. Users and administrators should update to a Linux kernel version that includes these fixes. No additional mitigation actions are specified or required beyond applying the official patch.

Description

CVE-2026-98942 is a vulnerability in the Linux kernel's scheduler extension (sched_ext) related to how cid tables are built and published. The issue arises because cid tables were visible to cid kernel functions while being modified, allowing racing tracing or syscall programs to read uninitialized or inconsistent memory. The fix involves building cid tables privately and publishing them with Read-Copy-Update (RCU) synchronization to ensure readers only see fully built tables. The vulnerability affects Linux kernel version 7.2.

Impact

Before the fix, programs using tracing or syscalls could race against the scheduler's cid table initialization and read uninitialized or inconsistent memory, potentially leading to information disclosure or kernel instability. The fix prevents exposure of uninitialized memory and ensures consistent table views during scheduler operations.

Summary

The Linux kernel sched_ext subsystem previously published global cid tables before fully initializing them, causing potential race conditions where tracing or syscall programs could read uninitialized memory or torn updates. The fix ties the cid tables' lifetimes to the root scheduler, building fresh tables privately and publishing them only after finalization using RCU. This ensures that any non-NULL global pointer references a fully built table valid for the duration of the RCU read section. Additionally, kernel functions that accessed these tables without proper RCU or preemption protection were corrected. The patch is identified by fixed commits 3a773220d39ba993dfe5d135f8b610be10794d5d and 0e1a74369bdbc357d3d9713734418d914a981553.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:35 UTC

Technical details

References

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