VulnerabilityPublished 18 Oct 2026

CVE-2026-98629: Linux kernel · net/sched: cls_u32: fix manual hash table handle IDR aliasing

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f6696481eedfd5752b4b56eed715d0b0fe48b9c5 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f6696481eedfd5752b4b56eed715d0b0fe48b9c5, 54a454c5e41f5e2cb70c8163140ce095c5d5eefd, 21fc07924e996e1e661268ca269c86b8d59d25b3 +6

Exploitation evidence

Disclosed: evidence found.
CVE published 18 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 to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=6.1.119 <6.1.189 >=6.6.63 <6.6.158 >=6.11.10 <6.12	Fixed in f6696481eedfd5752b4b56eed715d0b0fe48b9c5 54a454c5e41f5e2cb70c8163140ce095c5d5eefd 21fc07924e996e1e661268ca269c86b8d59d25b3 6.12 6.6.158 6.1.189 2f898f9ec7c73c5697ee462681e7ea6984ee1f3d 0fac292d93fdb313099e98cce928b3a524c92c94 0a5f5d9e94dead312d32c366b917c64e552b72f7
LinuxLinux	Affected =6.12	Fixed in–

AI-suggested

A fix for this vulnerability is available in Linux kernel versions 6.1.189, 6.6.158, 6.12, and corresponding commits. Users should upgrade to these fixed versions or later to remediate the issue. No additional mitigation steps are required as the patch addresses the root cause by correcting handle keying and allocation logic.

Description

CVE-2026-98629 is a vulnerability in the Linux kernel's net/sched cls_u32 component involving improper handling of manual hash table handles that causes IDR aliasing. This flaw leads to permanent resource leaks and potential misrouting of network traffic due to handle collisions between manual and auto-allocated tables. The issue affects certain Linux kernel versions prior to fixed releases and has been resolved by aligning allocation and removal key domains and rejecting conflicting manual handles.

Impact

The vulnerability causes permanent resource leaks in the kernel's u32 hash tables and can lead to incorrect routing of network traffic due to handle aliasing between manual and auto-allocated tables. This may disrupt network filtering and classification functions relying on cls_u32, potentially affecting system stability or network behavior. There is no indication of remote code execution or privilege escalation. No known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel's net/sched cls_u32 module arises from inconsistent keying of IDR entries for u32 hash tables created with explicit handles. Manual tables key their IDR entries on the raw handle, while destroy operations free entries using a transformed handle2id(handle) value. This discrepancy causes manual tables' IDR entries to become unreachable on deletion, resulting in permanent leaks, and can cause deletion of unrelated auto-allocated tables' IDR entries. Consequently, later auto allocations may reuse handles that alias live manual tables, causing lookups and routing to incorrectly reference the wrong table. The fix ensures allocation and removal share the same key domain by keying divisor-path allocations on handle2id(handle), rejecting manual handles that conflict with existing IDs, and preventing auto allocation from using IDs held by live manual tables.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:07 UTC

Technical details

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