CVE-2022-49921

Kernel memory corruption via stale skb access

Published May 1, 2025 · Updated Aug 5, 2026

Use-after-free in Linux kernel network scheduling allows local users to corrupt kernel memory through a configured RED qdisc hierarchy. red_enqueue passes an skb to qdisc_enqueue, which can consume and free it, and then incorrectly reads skb->len while updating backlog accounting. Local low-privileged access is required; successful exploitation can disclose or alter kernel data and interrupt the system.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel network scheduling allows local users to corrupt kernel memory through a configured RED qdisc hierarchy. red_enqueue passes an skb to qdisc_enqueue, which can consume and free it, and then incorrectly reads skb->len while updating backlog accounting. Local low-privileged access is required; successful exploitation can disclose or alter kernel data and interrupt the system.

The record

CVE
CVE-2022-49921
Published
May 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=4.4.163 <4.5
  2. Affected versionversion=4.7
  3. Affected versionversion=ab0b3b9dbf559a5633d460e748144697bd2d3aa3
  4. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <170e5317042c302777ed6d59fdb84af9b0219d4e
  5. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <52e0429471976785c155bfbf51d80990c6cd46e2
  6. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <5960b9081baca85cc7dcb14aec1de85999ea9d36
  7. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <795afe0b9bb6c915f0299a8e309936519be01619
  8. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <8bdc2acd420c6f3dd1f1c78750ec989f02a1e2b9
  9. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <a238cdcf2bdc72207c74375fc8be13ee549ca9db
  10. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <e877f8fa49fbccc63cb2df2e9179bddc695b825a
  11. Affected versionversion=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <fc4b50adb400ee5ec527a04073174e8e73a139fa

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.4.163 <4.5; version=4.7; version=ab0b3b9dbf559a5633d460e748144697bd2d3aa3; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <170e5317042c302777ed6d59fdb84af9b0219d4e; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <52e0429471976785c155bfbf51d80990c6cd46e2; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <5960b9081baca85cc7dcb14aec1de85999ea9d36; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <795afe0b9bb6c915f0299a8e309936519be01619; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <8bdc2acd420c6f3dd1f1c78750ec989f02a1e2b9; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <a238cdcf2bdc72207c74375fc8be13ee549ca9db; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <e877f8fa49fbccc63cb2df2e9179bddc695b825a; version=d7f4f332f082c4d4ba53582f902ed6b44fd6f45e <fc4b50adb400ee5ec527a04073174e8e73a139fa

Published CVSS scores

7.8NISTCVSS: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

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-416Use After Free
T1068Exploitation for Privilege Escalation

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

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Your stack

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