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Fencer Vulns
medium 5.5

CVE-2026-31738 json

vxlan: validate ND option lengths in vxlan_na_create

published 2026-05-01 6 mo ago modified 2026-11-06 3 d ago also EUVD-2026-26551

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

vxlan: validate ND option lengths in vxlan_na_create

vxlan_na_create() walks ND options according to option-provided lengths. A malformed option can make the parser advance beyond the computed option span or use a too-short source LLADDR option payload.

Validate option lengths against the remaining NS option area before advancing, and only read source LLADDR when the option is large enough for an Ethernet address.

Patch / fix

  • Linux Linux 3.13, 3.14, 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0
  • linux Debian 12 6.1.170-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.12-1

debian advisories DEBIAN-CVE-2026-31738

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1108.114
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67

ubuntu advisories UBUNTU-CVE-2026-31738

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-livepatch-MICRO-6-0-RT_Update_12 Linux Micro 6.1, Linux Micro 6.0 14-1.1
  • kernel-livepatch-MICRO-6-0-RT_Update_13 Linux Micro 6.1, Linux Micro 6.0 10-1.1
  • kernel-livepatch-MICRO-6-0-RT_Update_11 Linux Micro 6.1, Linux Micro 6.0 15-1.1
  • kernel-livepatch-MICRO-6-0-RT_Update_10 Linux Micro 6.1, Linux Micro 6.0 19-1.1
  • kernel-livepatch-SLE16_Update_0 Linux Micro 6.2 16-160000.4.3
  • kernel-livepatch-SLE16_Update_2 Linux Micro 6.2 12-160000.1.1
  • kernel-livepatch-SLE16_Update_1 Linux Micro 6.2 14-160000.1.1
  • kernel-livepatch-SLE16_Update_4 Linux Micro 6.2 10-160000.1.1

suse advisories SUSE-SU-2026:23045-1SUSE-SU-2026:23046-1SUSE-SU-2026:23107-1SUSE-SU-2026:23108-1SUSE-SU-2026:23044-1SUSE-SU-2026:23106-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-31738 updated cvss 5.5

kernel: vxlan: validate ND option lengths in vxlan_na_create

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “To mitigate this issue, prevent the vxlan module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.