CVE-2026-74564

Firewall verdict manipulation via mixed-mode hashtable reuse

Published Aug 15, 2026 · Updated Aug 15, 2026

Uninitialized memory access in the Linux kernel allows local users to read stale kernel data and manipulate firewall match verdicts. xt_hashlimit reuses a named hashtable across standard and rate-match rules without checking their incompatible union layouts, so hashlimit_mt_common reads an uninitialized burst field and overwrites other rate state. Exploitation requires CAP_NET_ADMIN and conflicting rules in one network namespace; effects remain confined to stale slab-data exposure and incorrect packet classification in that namespace.

CVSS severity7.1
High
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

Uninitialized memory access in the Linux kernel allows local users to read stale kernel data and manipulate firewall match verdicts. xt_hashlimit reuses a named hashtable across standard and rate-match rules without checking their incompatible union layouts, so hashlimit_mt_common reads an uninitialized burst field and overwrites other rate state. Exploitation requires CAP_NET_ADMIN and conflicting rules in one network namespace; effects remain confined to stale slab-data exposure and incorrect packet classification in that namespace.

The record

CVE
CVE-2026-74564
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1562.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=4.14
  2. Affected versionversion=bea74641e3786d51dcf1175527cc1781420961c9 <06a76334243ccd875a981aa8bb46c0f931ef1e3b
  3. Affected versionversion=bea74641e3786d51dcf1175527cc1781420961c9 <24683fea1f06bd3bd2707b99460e859bc6464c22
  4. Affected versionversion=bea74641e3786d51dcf1175527cc1781420961c9 <305b63e1402267459fdabb183af4527f6799eebf
  5. Affected versionversion=bea74641e3786d51dcf1175527cc1781420961c9 <32ec8d4aba2cf22e12bdc28df8c4bd833c195fc0
  6. Affected versionversion=bea74641e3786d51dcf1175527cc1781420961c9 <d186f77d18bdfb252d401ff992ca3001a6a65a0f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.14; version=bea74641e3786d51dcf1175527cc1781420961c9 <06a76334243ccd875a981aa8bb46c0f931ef1e3b; version=bea74641e3786d51dcf1175527cc1781420961c9 <24683fea1f06bd3bd2707b99460e859bc6464c22; version=bea74641e3786d51dcf1175527cc1781420961c9 <305b63e1402267459fdabb183af4527f6799eebf; version=bea74641e3786d51dcf1175527cc1781420961c9 <32ec8d4aba2cf22e12bdc28df8c4bd833c195fc0; version=bea74641e3786d51dcf1175527cc1781420961c9 <d186f77d18bdfb252d401ff992ca3001a6a65a0f

Published CVSS scores

7.1UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
7.1Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
2.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
4.4SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
4.4Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

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

T1562.004Impair Defenses: Disable or Modify System Firewall

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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