VulnerabilityPublished 18 Oct 2026

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

Source GCVE Database

Authoritative record:CVE-2026-98629· Medium

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 by Threat Radar · 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.

ghsa-3xrv-9p49-wqm3

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 is available that aligns the key domains used for manual and auto-allocated handles, preventing aliasing and leaks. Users should apply the official Linux kernel patch that addresses this issue. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation. Patch status is not explicitly stated in the input data; therefore, check the vendor advisory or Linux kernel mailing lists for the current patch availability and guidance.

Description

A vulnerability in the Linux kernel's net/sched cls_u32 component causes improper handling of manual hash table handles, leading to permanent memory leaks and potential misrouting of network traffic. The issue arises because manual hash tables use a different key domain than auto-allocated tables, causing aliasing and incorrect deletions. This flaw has been fixed by aligning the key domains and rejecting manual handles that conflict with existing IDs.

Impact

The vulnerability leads to permanent memory leaks in the kernel's traffic control subsystem and can cause incorrect routing of network traffic due to handle aliasing. This may affect network packet filtering and classification, potentially disrupting network operations or causing unexpected behavior in traffic control rules.

Summary

The Linux kernel vulnerability (CVE-2026-98629) affects the net/sched cls_u32 module, where a u32 hash table created with an explicit handle keys its IDR entry on the raw handle, but deletion frees it under a different key domain (handle2id(handle)). This mismatch causes manual tables to leak entries permanently and can cause deletion of unrelated auto-allocated tables. Consequently, later auto allocations may alias live manual tables, causing lookups and routing to the wrong table. The fix involves keying the divisor-path allocation on handle2id(handle) to unify the key domain, rejecting manual handles that map onto already used IDs, and ensuring auto allocation skips IDs held by live manual tables.

References

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