CVE-2026-74621Network attack vector

Remote denial of service via sk_buff ownership leak

Published Aug 22, 2026 · Updated Aug 25, 2026

Memory leak in affected Linux kernel branches allows remote attackers to exhaust kernel memory by sending malformed IP packets. The tcf_ct_act error path returns TC_ACT_CONSUMED after header validation fails without freeing or queueing the still-owned sk_buff and data buffer. Exposure requires CONFIG_NET_ACT_CT and a clsact chain using action ct; every rejected packet leaks memory without bound until service interruption.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in affected Linux kernel branches allows remote attackers to exhaust kernel memory by sending malformed IP packets. The tcf_ct_act error path returns TC_ACT_CONSUMED after header validation fails without freeing or queueing the still-owned sk_buff and data buffer. Exposure requires CONFIG_NET_ACT_CT and a clsact chain using action ct; every rejected packet leaks memory without bound until service interruption.

The record

CVE
CVE-2026-74621
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 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

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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=0b5b831122fc3789fff75be433ba3e4dd7b779d4 <23e97d594ddd0153020c506d5041048fbde1beb4
  2. Affected versionversion=172ba7d46c202e679f3ccb10264c67416aaeb1c4 <b5dbecc2016e1692fd1c2532af9c41ba729cb747
  3. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <439d3e404f9d5e515911cc8132cde198b337c19e
  4. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <47d99828591d0fe8be4b9c8992ff3b8e47968db9
  5. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <8a7ed561671aa6a911a2de99e59ef670a4d0b1df
  6. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <b47bb899e04b5407c5a63fe88d4b6676586a6e84
  7. Affected versionversion=5.15.148 <5.15.217
  8. Affected versionversion=6.1.75 <6.1.184
  9. Affected versionversion=6.6.14 <6.6.152
  10. Affected versionversion=6.7.2 <6.8
  11. Affected versionversion=6.8
  12. Affected versionversion=73f7da5fd124f2cda9161e2e46114915e6e82e97 <737873a59905a54ca0d2d127ef882f3f88bf4379
  13. Affected versionversion=f5346df0591d10bc948761ca854b1fae6d2ef441

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0b5b831122fc3789fff75be433ba3e4dd7b779d4 <23e97d594ddd0153020c506d5041048fbde1beb4; version=172ba7d46c202e679f3ccb10264c67416aaeb1c4 <b5dbecc2016e1692fd1c2532af9c41ba729cb747; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <439d3e404f9d5e515911cc8132cde198b337c19e; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <47d99828591d0fe8be4b9c8992ff3b8e47968db9; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <8a7ed561671aa6a911a2de99e59ef670a4d0b1df; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <b47bb899e04b5407c5a63fe88d4b6676586a6e84; version=5.15.148 <5.15.217; version=6.1.75 <6.1.184; version=6.6.14 <6.6.152; version=6.7.2 <6.8; version=6.8; version=73f7da5fd124f2cda9161e2e46114915e6e82e97 <737873a59905a54ca0d2d127ef882f3f88bf4379; version=f5346df0591d10bc948761ca854b1fae6d2ef441

Published CVSS scores

7.5LinuxCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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