CVE-2026-74544

Undefined behavior via unchecked u32 filter offshift

Published Aug 15, 2026 · Updated Aug 15, 2026

Shift-out-of-bounds in Linux kernel 2.6.12 through 7.1.7 allows local users to trigger undefined behavior through a crafted u32 filter. u32_change() stores tc_u32_sel.offshift without bounds validation, and u32_classify() right-shifts a promoted 16-bit value by that input. An unprivileged user can reach the path through user and network namespaces; the report demonstrates a UBSAN fault but not a crash or code execution.

CVSS severity7.8
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Shift-out-of-bounds in Linux kernel 2.6.12 through 7.1.7 allows local users to trigger undefined behavior through a crafted u32 filter. u32_change() stores tc_u32_sel.offshift without bounds validation, and u32_classify() right-shifts a promoted 16-bit value by that input. An unprivileged user can reach the path through user and network namespaces; the report demonstrates a UBSAN fault but not a crash or code execution.

The record

CVE
CVE-2026-74544
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
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

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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <313cb9ffc4101a885d791facf4b5ea3d5e06144d
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <aef96eead2860cbfa371e4471d4f04412213b958
  3. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <313cb9ffc4101a885d791facf4b5ea3d5e06144d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <aef96eead2860cbfa371e4471d4f04412213b958; version=2.6.12

Published CVSS scores

6.9SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
7.8Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.6SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

No sourced classifications are available.

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo