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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98491: net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 26b2bd70d22457556e2fa01cbf1192cb1a94d619, 37e3c878b183a115f9a114067f9ef3b408ad27fb, 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 26b2bd70d22457556e2fa01cbf1192cb1a94d619, 37e3c878b183a115f9a114067f9ef3b408ad27fb, 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up committing both 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 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 committing both clones without modifications into the same zone is needed. So, let's just reset the entry in case for some reason we got an skb with a shared one during commit. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 18, 2026
Updated
Oct 24, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-98491

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.3affected
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before e0fa5ea434b7e8467ef3adc64e3858b1ca2a642daffected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before 37e3c878b183a115f9a114067f9ef3b408ad27fbaffected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before 707c2dc77891a874f4e8c52c285a511079164ec8affected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before de41ee24f77b0fc45397db3e277cae2adbd43dfeaffected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before 55e5256adf3940e71802e2f749cacf81518726b0affected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before e2829ae5459ddb5fce526b2e84697edf6c0c3cefaffected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55affected · git
    • cae3a2627520c3795b54533c5328b77af3405dbe and later · before 26b2bd70d22457556e2fa01cbf1192cb1a94d619affected · git
    • before 4.3not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.9-17.2.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98489Oct 18, 2026 · net: atl1c: fix soft lockup on out-of-range tpd_cons read
    0Monitor
  • ← EarlierCVE-2026-98490Oct 18, 2026 · net: openvswitch: conntrack: fix helper UAF due to extensions realloc
    39Monitor
  • Later →CVE-2026-98492Oct 18, 2026 · net: macb: fix dma_alloc_coherent() leak on macb_alloc() error paths
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux26b2bd70d22457556e2fa01cbf1192cb1a94d619Vendor (CNA)
Linux Linux37e3c878b183a115f9a114067f9ef3b408ad27fbVendor (CNA)
Linux Linux457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55Vendor (CNA)
Linux Linux55e5256adf3940e71802e2f749cacf81518726b0Vendor (CNA)
Linux Linux707c2dc77891a874f4e8c52c285a511079164ec8Vendor (CNA)
Linux Linuxde41ee24f77b0fc45397db3e277cae2adbd43dfeVendor (CNA)
Linux Linuxe0fa5ea434b7e8467ef3adc64e3858b1ca2a642dVendor (CNA)
Linux Linuxe2829ae5459ddb5fce526b2e84697edf6c0c3cefVendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.159.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 5, 2026+18 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records