net/sched: act_ct: avoid modifying shared unconfirmed ct entry
Assessment
- Severity
- Important
- CVSS base score
- 8.1CVSS:3.1/
AV:N/ AC:H/ PR:N/ UI:N/ S:U/ C:H/ 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.
- Attack vector
- NetworkAV:N
- Attack complexity
- HighAC:H
- Privileges required
- NonePR:N
- User interaction
- NoneUI:N
- Scope
- UnchangedS:U
- Confidentiality
- HighC:H
- Integrity
- HighI:H
- Availability
- HighA:H
Updates that fix it
0 KBsNo 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 20 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 01:09 UTC → 21 Oct 2026 18:33 UTC
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Explore global source statements, affected packages and advisory history for CVE-2026-98441. The catalog has a separate collection scope from Microsoft release records.
Collected exploitation and prediction evidence
Risk source coverageCISA 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-2026-98441
Publishednet/sched: act_ct: avoid modifying shared unconfirmed ct entry
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up processing both again but with different sets of extensions. The series of events: 1. The first clone wants to commit and runs the helpers wiring up the extension pointer into the expectation list. 2. Then it looses the confirmation keeping the entry unconfirmed. 3. Second clone now wants to commit labels or run NAT and adds the new extension for that breaking the pointer in the expectation list causing UAF on the destruction path later. While this is possible to trigger, there should be no practical network pipeline where we need to process both clones without modifications in the same zone. So, let's just reset the entry in case for some reason we got an skb with a shared one. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. Unlike openvswitch module, act_ct allows for NAT without commit. Changing that would be a uAPI break. So, act_ct needs to reset on NAT regardless of the commit flag to avoid reallocation of the extension space. This, however, doesn't really change the picture for sensible networking cases as there should be no need to run the same packet twice (before and after the clone) through conntrack without packet header or zone changes and without commit. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing.
- Source published
- 18 Oct 2026 15:14:51 UTC
- Source modified
- 24 Oct 2026 14:08:49 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
This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.
CVSS 3.1 · 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H