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NVD / CVE Program· CNA Linux

CVE-2026-68123: openvswitch: fix GSO userspace truncation underflow

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.55% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 100a23b1613e9218e0af654ef102352c713f0263, 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6, 4032f8ed10fcb84d41c508dfb04be96589f78dfe; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 100a23b1613e9218e0af654ef102352c713f0263, 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6, 4032f8ed10fcb84d41c508dfb04be96589f78dfe; azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 6.6.150.1-1 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: openvswitch: fix GSO userspace truncation underflow OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb length in OVS_CB(skb)->cutlen. When a later userspace action segments a GSO skb, queue_gso_packets() reuses that delta for each smaller segment. A segment can then reach queue_userspace_packet() with cutlen greater than skb->len, underflowing the length passed to skb_zerocopy(). Store the maximum preserved length instead and bound each consumer against the current skb length. Use U32_MAX as the no-truncation sentinel so the value remains valid if skb geometry changes before a consumer handles it.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Aug 10, 2026
Updated
Oct 19, 2026
EPSS
0.5% · 46th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
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.

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

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  • when exploit code appears or is weaponized
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  • 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

    • 4.8affected
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before 50a6a85f3d6b1d22d8436848606cdef5d2c490b4affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before e211b081901ffca76674082c73eeaed53524c369affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dcaffected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before 100a23b1613e9218e0af654ef102352c713f0263affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before ea85dbcbe8d4056ecb54352f97743d138ea4c407affected · git
    • f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 and later · before 4032f8ed10fcb84d41c508dfb04be96589f78dfeaffected · git
    • before 4.8not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.65.1.el10_26.12.0-211.65.1.el10_2

+96

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-2026-68118Aug 10, 2026 · tcp: challenge ACK for non-exact RST in SYN-RECEIVED
    32Monitor
  • ← EarlierCVE-2026-68121Aug 10, 2026 · pppoe: reload header pointer after dev_hard_header()
    31Monitor
  • Later →CVE-2026-68125Aug 10, 2026 · mac802154: llsec: reject frames shorter than the authentication tag
    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 Linux100a23b1613e9218e0af654ef102352c713f0263Vendor (CNA)
Linux Linux2623c48cc3a8da9a1886fd8f65c0e348f4406fd6Vendor (CNA)
Linux Linux4032f8ed10fcb84d41c508dfb04be96589f78dfeVendor (CNA)
Linux Linux50a6a85f3d6b1d22d8436848606cdef5d2c490b4Vendor (CNA)
Linux Linuxa16eaaf7c0b0ccdef6166707d90ffbc6eebf6855Vendor (CNA)
Linux Linuxe211b081901ffca76674082c73eeaed53524c369Vendor (CNA)
Linux Linuxea85dbcbe8d4056ecb54352f97743d138ea4c407Vendor (CNA)
Linux Linuxfbfa3ad2ad6f3a5624aba5211c46290fb98cc9dcVendor (CNA)
azl3 kernel 6.6.143.1-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.65.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.101-1~deb12u1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.65.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+6

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.

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.

  • CVE-2026-720035 days apartwifi: brcmfmac: cyw: fix heap overflow on a short auth frame
    35Monitor

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).

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

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • 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
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-191 · Integer Underflow (Wrap or Wraparound)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/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. 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