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NVD / CVE Program· CNA Linux

CVE-2026-31407: netfilter: conntrack: add missing netlink policy validations

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.17% (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 0fbae1e74493d5a160a70c51aeba035d8266ea7d, 67c53c1978cef3c504237275e39c857e2f6af56e, 78bba9f73942aa7dca47d817d8cec0fb9b443b70; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1.

Low priority for now. Upgrade to Linux Linux 0fbae1e74493d5a160a70c51aeba035d8266ea7d, 67c53c1978cef3c504237275e39c857e2f6af56e, 78bba9f73942aa7dca47d817d8cec0fb9b443b70; azl3 kernel 6.6.134.1-2 on Azure Linux 3.0 6.6.137.1-1 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: netfilter: conntrack: add missing netlink policy validations Hyunwoo Kim reports out-of-bounds access in sctp and ctnetlink. These attributes are used by the kernel without any validation. Extend the netlink policies accordingly. Quoting the reporter: nlattr_to_sctp() assigns the user-supplied CTA_PROTOINFO_SCTP_STATE value directly to ct->proto.sctp.state without checking that it is within the valid range. [..] and: ... with exp->dir = 100, the access at ct->master->tuplehash[100] reads 5600 bytes past the start of a 320-byte nf_conn object, causing a slab-out-of-bounds read confirmed by UBSAN.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Apr 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.1
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-2026-31407

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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.27 and later · before 6.6.136
  • linux linux kernel6.7 and later · before 6.12.83
  • linux linux kernel6.13 and later · before 6.18.24
  • linux linux kernel6.19 and later · before 6.19.10
  • linux linux kernel7.0

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

    • 2.6.27affected
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before e7b5766693477c52424cc6c79dd30a7a9c7db52caffected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before 78bba9f73942aa7dca47d817d8cec0fb9b443b70affected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before be88a337bf07afb1ee173f1099294d1b7ab3fefeaffected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before c5e918390002edf0cff80a0e7ce1f86f16a9507caffected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before 9174d28f3f15d8c4962f5980c0be167633880443affected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before 67c53c1978cef3c504237275e39c857e2f6af56eaffected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before 0fbae1e74493d5a160a70c51aeba035d8266ea7daffected · git
    • a258860e01b80e8f554a4ab1a6c95e6042eb8b73 and later · before f900e1d77ee0ef87bfb5ab3fe60f0b3d8ad5ba05affected · git
    • before 2.6.27not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.10-16.19.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-31406Apr 6, 2026 · xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()
    31Monitor
  • ← EarlierCVE-2026-31409Apr 6, 2026 · ksmbd: unset conn->binding on failed binding request
    35Monitor
  • Later →CVE-2026-31408Apr 6, 2026 · Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold
    35Monitor

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 Linux0fbae1e74493d5a160a70c51aeba035d8266ea7dVendor (CNA)
Linux Linux67c53c1978cef3c504237275e39c857e2f6af56eVendor (CNA)
Linux Linux78bba9f73942aa7dca47d817d8cec0fb9b443b70Vendor (CNA)
Linux Linux9174d28f3f15d8c4962f5980c0be167633880443Vendor (CNA)
Linux Linuxbe88a337bf07afb1ee173f1099294d1b7ab3fefeVendor (CNA)
Linux Linuxc5e918390002edf0cff80a0e7ce1f86f16a9507cVendor (CNA)
Linux Linuxe7b5766693477c52424cc6c79dd30a7a9c7db52cVendor (CNA)
Linux Linuxf900e1d77ee0ef87bfb5ab3fe60f0b3d8ad5ba05Vendor (CNA)
azl3 kernel 6.6.134.1-2 on Azure Linux 3.06.6.137.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.176-1 · 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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

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.

—

Bug bounty scope

No known public program.

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

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
none
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
None
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records