CVE-2021-46915

Kernel crash via truncated nftables limit divisor

Published Feb 27, 2024 · Updated May 11, 2026

A divide error in the Linux kernel nftables limit expression allows local users to crash the kernel through a crafted netlink request. The nft_limit_init function passes a 64-bit divisor to div_u64, whose 32-bit divisor parameter truncates a large rate value to zero before division. Reaching the fault requires local access to submit an nftables set expression, and successful exploitation interrupts the entire system by crashing the kernel.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A divide error in the Linux kernel nftables limit expression allows local users to crash the kernel through a crafted netlink request. The nft_limit_init function passes a 64-bit divisor to div_u64, whose 32-bit divisor parameter truncates a large rate value to zero before division. Reaching the fault requires local access to submit an nftables set expression, and successful exploitation interrupts the entire system by crashing the kernel.

The record

CVE
CVE-2021-46915
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-369, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=4.13
  2. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <01fb1626b620cb37a65ad08e0f626489e8f042ef
  3. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <1bb3ee4259936cc3b2d80a4a480bbb4868575071
  4. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <9065ccb9ec92c5120e7e97958397ebdb454f23d6
  5. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <b895bdf5d643b6feb7c60856326dd4feb6981560
  6. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <dc1732baa9da5b68621586bf8636ebbc27dc62d2
  7. Affected versionversion=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <fadd3c4afdf3d4c21f4d138502f8b76334987e26

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.13; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <01fb1626b620cb37a65ad08e0f626489e8f042ef; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <1bb3ee4259936cc3b2d80a4a480bbb4868575071; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <9065ccb9ec92c5120e7e97958397ebdb454f23d6; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <b895bdf5d643b6feb7c60856326dd4feb6981560; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <dc1732baa9da5b68621586bf8636ebbc27dc62d2; version=c26844eda9d4fdbd266660e3b3de2d0270e3a1ed <fadd3c4afdf3d4c21f4d138502f8b76334987e26

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-369Divide By Zero
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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