CVE-2026-74579

Kernel crash or policy bypass via oversized mask

Published Aug 17, 2026 · Updated Aug 25, 2026

Incorrect bit shifting in the Linux netfilter nft_payload component allows local users to corrupt offloaded filtering policy or crash the kernel. nft_payload_offload_mask() shifts a 32-bit integer by up to 120 bits and trims only one mask word, so partial-field rules retain trailing 0xff bytes. Reaching the flaw requires CAP_NET_ADMIN and an nftables netdev ingress chain with hardware offload; the resulting mask can misapply packet actions or trigger a kernel panic.

CVSS severity7.1
High
EPSS probability0.12%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect bit shifting in the Linux netfilter nft_payload component allows local users to corrupt offloaded filtering policy or crash the kernel. nft_payload_offload_mask() shifts a 32-bit integer by up to 120 bits and trims only one mask word, so partial-field rules retain trailing 0xff bytes. Reaching the flaw requires CAP_NET_ADMIN and an nftables netdev ingress chain with hardware offload; the resulting mask can misapply packet actions or trigger a kernel panic.

The record

CVE
CVE-2026-74579
Published
Aug 17, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-1335, T1562.004, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=5.10
  2. Affected versionversion=5.9.14 <5.10
  3. Affected versionversion=5c2b4b4f9fa5b765b927e361e3d310bcb5773015
  4. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <16b553c46e347bc9de9946c4960654d5884a86de
  5. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <363c3a84a946d53e5e121c9f47c7c2b7d228c46b
  6. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <39e88f28fb32bf02bd4b525c24c842c9cff5663d
  7. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7
  8. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <630295d5bba1d0e0f494cc459452eb0a0058c545
  9. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <8720df4504e0ed1781a702f65251bd47b3534d5e
  10. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <a375d8ace807767f29f276b681b6324c74929b1d
  11. Affected versionversion=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <b19b5d2e042c294e2cc1c908dc598f9d64015396

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=5.9.14 <5.10; version=5c2b4b4f9fa5b765b927e361e3d310bcb5773015; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <16b553c46e347bc9de9946c4960654d5884a86de; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <363c3a84a946d53e5e121c9f47c7c2b7d228c46b; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <39e88f28fb32bf02bd4b525c24c842c9cff5663d; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <630295d5bba1d0e0f494cc459452eb0a0058c545; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <8720df4504e0ed1781a702f65251bd47b3534d5e; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <a375d8ace807767f29f276b681b6324c74929b1d; version=a5d45bc0dc50f9dd83703510e9804d813a9cac32 <b19b5d2e042c294e2cc1c908dc598f9d64015396

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
7.1LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
5.5Red HatCVSS: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-1335Incorrect Bitwise Shift of Integer
T1562.004Disable or Modify System Firewall
T1499Endpoint Denial of Service

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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