CVE-2026-74739Public exploit

Local kernel compromise via cls_u32 type confusion

Published Aug 26, 2026 · Updated Aug 26, 2026

Out-of-bounds access in the Linux kernel cls_u32 classifier allows local users to compromise the host kernel through traffic-control operations. u32_walk() passes hash nodes and key nodes to u32_bind_class(), which casts every entry as tc_u_knode and accesses a nonexistent tcf_result in hash nodes. Triggering the path requires CAP_NET_ADMIN; the invalid access can expose kernel memory, corrupt adjacent slab objects, or panic the host.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in the Linux kernel cls_u32 classifier allows local users to compromise the host kernel through traffic-control operations. u32_walk() passes hash nodes and key nodes to u32_bind_class(), which casts every entry as tc_u_knode and accesses a nonexistent tcf_result in hash nodes. Triggering the path requires CAP_NET_ADMIN; the invalid access can expose kernel memory, corrupt adjacent slab objects, or panic the host.

The record

CVE
CVE-2026-74739
Published
Aug 26, 2026
Updated
Aug 26, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 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=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <19d114b93c94bdef70496f26685c2a6b242f41b3
  2. Affected versionversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <31f26a95eeee926946809ac456c61a3217936a62
  3. Affected versionversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <594a064d603202b9ee21e07679d854e5c1750cc4
  4. Affected versionversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <6d3724e616faf952c3adcf8414fc21a828ef3709
  5. Affected versionversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <e71f8e9ed6f311410b14741f6012afe01869c0fa
  6. Affected versionversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <ec5f3005586a785689fd568361b0c5925cb1548b
  7. Affected versionversion=4.14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <19d114b93c94bdef70496f26685c2a6b242f41b3; version=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <31f26a95eeee926946809ac456c61a3217936a62; version=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <594a064d603202b9ee21e07679d854e5c1750cc4; version=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <6d3724e616faf952c3adcf8414fc21a828ef3709; version=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <e71f8e9ed6f311410b14741f6012afe01869c0fa; version=07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1 <ec5f3005586a785689fd568361b0c5925cb1548b; version=4.14

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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 exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1068Exploitation for Privilege Escalation

Public exploit references

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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