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NVD / CVE Program· CNA Linux

CVE-2026-31679: openvswitch: validate MPLS set/set_masked payload length

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: 0.16% (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 2ca33b88a79ca42f017ae0f7011280325655438e, 4cae986225f8b8679ad86b924918e7d75a96aa61, 546b68ac893595877ffbd7751e5c55fd1c43ede6; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2.

Low priority for now. Upgrade to Linux Linux 2ca33b88a79ca42f017ae0f7011280325655438e, 4cae986225f8b8679ad86b924918e7d75a96aa61, 546b68ac893595877ffbd7751e5c55fd1c43ede6; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2 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: openvswitch: validate MPLS set/set_masked payload length validate_set() accepted OVS_KEY_ATTR_MPLS as variable-sized payload for SET/SET_MASKED actions. In action handling, OVS expects fixed-size MPLS key data (struct ovs_key_mpls). Use the already normalized key_len (masked case included) and reject non-matching MPLS action key sizes. Reject invalid MPLS action payload lengths early.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Apr 25, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 5th 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-2026-31679

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 kernel5.5 and later · before 5.10.253
  • linux linux kernel5.11 and later · before 5.15.203
  • linux linux kernel5.16 and later · before 6.1.168
  • linux linux kernel6.2 and later · before 6.6.131
  • linux linux kernel6.7 and later · before 6.12.80
  • linux linux kernel6.13 and later · before 6.18.21
  • linux linux kernel6.19 and later · before 6.19.11
  • 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

    • 5.5affected
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 68f32ef0683c8d1c05cd2e4f16818fa63ff59c6faffected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 4cae986225f8b8679ad86b924918e7d75a96aa61affected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 8ed7b9930cbc3bc71f868fa79a68700ac88d586aaffected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before c1f97152df8dfb17e855ddf0fc409b7bd13e9700affected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 98de18d327ef8cbbb704980e359e4872d8c28997affected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before bd50c7484c3bb34097571c1334174fb8b7408036affected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 2ca33b88a79ca42f017ae0f7011280325655438eaffected · git
    • fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 and later · before 546b68ac893595877ffbd7751e5c55fd1c43ede6affected · git
    • before 5.5not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.11-16.19.11-1

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-2026-31677Apr 25, 2026 · crypto: af_alg - limit RX SG extraction by receive buffer budget
    22Monitor
  • ← EarlierCVE-2026-31678Apr 25, 2026 · openvswitch: defer tunnel netdev_put to RCU release
    31Monitor
  • Later →CVE-2026-31680Apr 25, 2026 · net: ipv6: flowlabel: defer exclusive option free until RCU teardown
    31Monitor

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 Linux2ca33b88a79ca42f017ae0f7011280325655438eVendor (CNA)
Linux Linux4cae986225f8b8679ad86b924918e7d75a96aa61Vendor (CNA)
Linux Linux546b68ac893595877ffbd7751e5c55fd1c43ede6Vendor (CNA)
Linux Linux68f32ef0683c8d1c05cd2e4f16818fa63ff59c6fVendor (CNA)
Linux Linux8ed7b9930cbc3bc71f868fa79a68700ac88d586aVendor (CNA)
Linux Linux98de18d327ef8cbbb704980e359e4872d8c28997Vendor (CNA)
Linux Linuxbd50c7484c3bb34097571c1334174fb8b7408036Vendor (CNA)
Linux Linuxc1f97152df8dfb17e855ddf0fc409b7bd13e9700Vendor (CNA)
azl3 kernel 6.6.130.1-3 on Azure Linux 3.06.6.134.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.170-1 · 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.

  • CVE-2026-4611533 days apartblock: add pgmap check to biovec_phys_mergeable
    39Monitor
  • CVE-2026-5322161 days apartip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
    39Monitor
  • CVE-2026-6403785 days apartwifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled
    39Monitor
  • CVE-2026-6404685 days apartnet: tls: prevent chain-after-chain in plain text SG
    39Monitor
  • CVE-2026-4311411 days apartnetfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry
    37Monitor
  • CVE-2026-4626639 days apartinet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP
    36Monitor

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-20 · Improper Input Validation

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.

Change log

  1. SSVC exploitation— → none
  2. 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