CVE-2026-74620

Local denial of service via unchecked fallback verdict

Published Aug 22, 2026 · Updated Aug 22, 2026

Improper input validation in Linux kernel traffic control allows local users to cause a denial of service via crafted fallback actions. The act_gact and act_police paths store out-of-range TCA_GACT_PROB.paction and TCA_POLICE_RESULT verdicts without the primary-action range check, so TC_ACT_CONSUMED prevents sk_buff release. Creating the action requires local low-privileged access, and each matching packet leaks its buffer without bound until system availability is exhausted.

CVSS severity5.5
Medium
EPSS probability0.18%
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

Improper input validation in Linux kernel traffic control allows local users to cause a denial of service via crafted fallback actions. The act_gact and act_police paths store out-of-range TCA_GACT_PROB.paction and TCA_POLICE_RESULT verdicts without the primary-action range check, so TC_ACT_CONSUMED prevents sk_buff release. Creating the action requires local low-privileged access, and each matching packet leaks its buffer without bound until system availability is exhausted.

The record

CVE
CVE-2026-74620
Published
Aug 22, 2026
Updated
Aug 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-911, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 22, 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=5.3
  2. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <2e8df8c9190335475a3b64a159d3efd8cdd1cb73
  3. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <5344e01179baa37547ab29fd7b8614f83faa190c
  4. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <6bcb8839aa2d686964a4154650afc4db91e1c514
  5. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <725efc2ab4a40affc4e285a2dc4896d103948a6c
  6. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <883b56ae58fe657d8497806c7059646e9ba6dbd0
  7. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <92f00f1d4d204a428b38e26fce3baee144b6955d
  8. Affected versionversion=720f22fed81bc6fd1765db7014651b6718887bea <efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.3; version=720f22fed81bc6fd1765db7014651b6718887bea <2e8df8c9190335475a3b64a159d3efd8cdd1cb73; version=720f22fed81bc6fd1765db7014651b6718887bea <5344e01179baa37547ab29fd7b8614f83faa190c; version=720f22fed81bc6fd1765db7014651b6718887bea <6bcb8839aa2d686964a4154650afc4db91e1c514; version=720f22fed81bc6fd1765db7014651b6718887bea <725efc2ab4a40affc4e285a2dc4896d103948a6c; version=720f22fed81bc6fd1765db7014651b6718887bea <883b56ae58fe657d8497806c7059646e9ba6dbd0; version=720f22fed81bc6fd1765db7014651b6718887bea <92f00f1d4d204a428b38e26fce3baee144b6955d; version=720f22fed81bc6fd1765db7014651b6718887bea <efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4

Published CVSS scores

5.5Oracle LinuxCVSS: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.

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

CWE-911Improper Update of Reference Count
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

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