CVE-2021-46992

Kernel fault via overflowing nftables bucket calculation

Published Feb 28, 2024 · Updated Aug 5, 2026

Integer overflow in Linux kernel nftables before 5.13 allows local users to trigger undefined behavior through an oversized hash set. nft_hash_buckets multiplies the untrusted 32-bit set size before rounding it to a power of two, allowing the calculation to produce an invalid shift exponent. Reaching the path requires permission to create nftables sets through Netlink; the demonstrated consequence is an out-of-bounds shift, while upstream does not distinguish a hang from a crash.

CVSS severity7.1
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in Linux kernel nftables before 5.13 allows local users to trigger undefined behavior through an oversized hash set. nft_hash_buckets multiplies the untrusted 32-bit set size before rounding it to a power of two, allowing the calculation to produce an invalid shift exponent. Reaching the path requires permission to create nftables sets through Netlink; the demonstrated consequence is an out-of-bounds shift, while upstream does not distinguish a hang from a crash.

The record

CVE
CVE-2021-46992
Published
Feb 28, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <1e8ab479cfbe5751efccedb95afb9b112a5ba475
  2. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <2824cafc6a93792d9ad85939c499161214d84c4b
  3. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <72b49dd116ca00a46a11d5a4d8d7987f05ed9cd7
  4. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <a388d10961ff8578b1a6691945d406c0f33aa71b
  5. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <a54754ec9891830ba548e2010c889e3c8146e449
  6. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <c77e2ef18167ad334e27610ced9a7f6af5ec1787
  7. Affected versionversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <efcd730ddd6f25578bd31bfe703e593e2421d708
  8. Affected versionversion=4.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <1e8ab479cfbe5751efccedb95afb9b112a5ba475; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <2824cafc6a93792d9ad85939c499161214d84c4b; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <72b49dd116ca00a46a11d5a4d8d7987f05ed9cd7; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <a388d10961ff8578b1a6691945d406c0f33aa71b; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <a54754ec9891830ba548e2010c889e3c8146e449; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <c77e2ef18167ad334e27610ced9a7f6af5ec1787; version=0ed6389c483dc77cdbdd48de0ca7ce41723dd667 <efcd730ddd6f25578bd31bfe703e593e2421d708; version=4.9

Published CVSS scores

7.1NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.1Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

T1499.004Application or System Exploitation

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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