CVE-2026-31416

Local NFLOG message drop via undersized buffer

Published Apr 13, 2026 · Updated Apr 13, 2026

A Netfilter size miscalculation in affected Linux Kernel branches allows local users to drop an NFLOG netlink message. The nfulnl_log_packet size calculation reserves nla_total_size for the NLMSG_DONE terminator instead of nlmsg_total_size, omitting the netlink header from the allocated socket buffer. Triggering the affected NFLOG path requires local low-privileged access and causes a WARN splat and one message drop, with no other reported effects.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A Netfilter size miscalculation in affected Linux Kernel branches allows local users to drop an NFLOG netlink message. The nfulnl_log_packet size calculation reserves nla_total_size for the NLMSG_DONE terminator instead of nlmsg_total_size, omitting the netlink header from the allocated socket buffer. Triggering the affected NFLOG path requires local low-privileged access and causes a WARN splat and one message drop, with no other reported effects.

The record

CVE
CVE-2026-31416
Published
Apr 13, 2026
Updated
Apr 13, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=131172845aa2c804ffa9423455aee585061ea35e
  2. Affected versionversion=3.18
  3. Affected versionversion=3a758a2b78da2f49f7165678faf999e946a0c4b5
  4. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <607245c4dbb86d9a10dd8388da0fb82170a99b61
  5. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <6b419700e459fbf707ca1543b7c1b57a60fedb73
  6. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <6d52a4a0520a6696bdde51caa11f2d6821cd0c01
  7. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <761b45c661af48da6a065868d59ab1e1f64fd9b6
  8. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <88a8f56e6276f616baad4274c6b8e4683e26e520
  9. Affected versionversion=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <f08ffa3e1c8e36b6131f69c5eb23700c28cbd262
  10. Affected versionversion=add9183d993c12fb61ce0a674a424341d5be5b36
  11. Affected versionversion=b1fef6b81871a396f3b8702077333e769673c87b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=131172845aa2c804ffa9423455aee585061ea35e; version=3.18; version=3a758a2b78da2f49f7165678faf999e946a0c4b5; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <607245c4dbb86d9a10dd8388da0fb82170a99b61; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <6b419700e459fbf707ca1543b7c1b57a60fedb73; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <6d52a4a0520a6696bdde51caa11f2d6821cd0c01; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <761b45c661af48da6a065868d59ab1e1f64fd9b6; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <88a8f56e6276f616baad4274c6b8e4683e26e520; version=9dfa1dfe4d5e5e66a991321ab08afe69759d797a <f08ffa3e1c8e36b6131f69c5eb23700c28cbd262; version=add9183d993c12fb61ce0a674a424341d5be5b36; version=b1fef6b81871a396f3b8702077333e769673c87b

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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