CVE-2026-98442ImportantNetworkRevised 21 Oct

net/sched: act_ct: fix helper UAF due to extensions realloc

MSRC advisory NVD CVE.org

Assessment

Severity: Important
CVSS base score: 7.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:H
Impact: Not stated
EPSS, next 30 days: Not scored yet
Public exploit code: No Nuclei template lists it
Exploitability: Not assessed
Publicly disclosed: No
Customer action: Required: apply the update
Component: Mariner
Weakness: —
Issued by: Linux
Published: 20 Oct 2026 · October 2026
Last revised: 21 Oct 2026Information published.

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: HighAC:H
Privileges required: NonePR:N
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: LowC:L
Integrity: HighI:H
Availability: HighA:H

Updates that fix it

0 KBs

No KB listed

MSRC lists no downloadable update, which usually means a service-side fix or a release-notes update. Check the MSRC advisory.

Affected products

1 affected product

azl3 kernel 6.6.157.1-1 on Azure Linux 3.0

What changed

First observed 21 Oct 2026

23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: msrc-cvrfIncomplete → Current
23 Oct 2026 · 08:31:50 UTC Public exploit codeNo Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC CISA KEVNot listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC Source coverage: public-exploit-codeCurrent → Incomplete
23 Oct 2026 · 08:31:50 UTC Source coverage: first-epssCurrent → Incomplete
23 Oct 2026 · 08:31:50 UTC Source coverage: cisa-kevCurrent → Incomplete
23 Oct 2026 · 08:31:50 UTC Source coverage: msrc-cvrfCurrent → Incomplete

Show 1 more recent changes

21 Oct 2026 · 20:45:25 UTCLast revised 20 Oct 2026 14:45 UTC → 21 Oct 2026 18:33 UTC

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Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-98442

Published

net/sched: act_ct: fix helper UAF due to extensions realloc

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: fix helper UAF due to extensions realloc While calling the helpers, a raw pointer to the extensions area is wired into expectations list: -> nf_ct_helper() -> helper->help() -> nf_ct_expect_related_report() -> nf_ct_expect_insert() -> hlist_add_head_rcu(&exp->lnode, &master_help->expectations) In case the connection is not confirmed yet, more extensions can be added afterwards with *_ext_add() calls reallocating the extension space and leaving the now invalid pointer in the expectations list that is later accessed while removing the expectation. Make sure that helpers are called at the end after all the other extensions are already added. Note that the helper rejection now leaves the mark and labels set, but that's not different from how the NAT was handled before or how the mark and the labels were handled on confirmation failure. And there are no atomicity guarantees provided by the API anyway.

Source published: 18 Oct 2026 15:14:52 UTC
Source modified: 24 Oct 2026 14:08:50 UTC
Observed here: 24 Oct 2026 16:17:04 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 3.1 · 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H