CVE-2023-53021

Kernel compromise via taprio qdisc teardown race

Published Mar 27, 2025 · Updated Aug 5, 2026

Use-after-free in sch_taprio in affected Linux kernels allows local users to crash or compromise the kernel via a crafted taprio qdisc. An invalid TCA_RATE makes qdisc_create() call taprio_destroy() after the timer has queued the qdisc, leaving net_tx_action() to use freed memory. Triggering the local netlink path requires CAP_NET_ADMIN, obtainable in an enabled user and network namespace; the race permits kernel memory disclosure, corruption, or a crash.

CVSS severity7.8
High
EPSS probability0.19%
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 sch_taprio in affected Linux kernels allows local users to crash or compromise the kernel via a crafted taprio qdisc. An invalid TCA_RATE makes qdisc_create() call taprio_destroy() after the timer has queued the qdisc, leaving net_tx_action() to use freed memory. Triggering the local netlink path requires CAP_NET_ADMIN, obtainable in an enabled user and network namespace; the race permits kernel memory disclosure, corruption, or a crash.

The record

CVE
CVE-2023-53021
Published
Mar 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 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

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=4.20
  2. Affected versionversion=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <1200388a0b1c3c6fda48d4d2143db8f7e4ef5348
  3. Affected versionversion=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <3a415d59c1dbec9d772dbfab2d2520d98360caae
  4. Affected versionversion=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <c53acbf2facfdfabdc6e6984a1a38f5d38b606a1
  5. Affected versionversion=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <c60fe70078d6e515f424cb868d07e00411b27fbc
  6. Affected versionversion=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <d3b2d2820a005e43855fa71b80c4a4b194201c60

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.20; version=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <1200388a0b1c3c6fda48d4d2143db8f7e4ef5348; version=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <3a415d59c1dbec9d772dbfab2d2520d98360caae; version=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <c53acbf2facfdfabdc6e6984a1a38f5d38b606a1; version=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <c60fe70078d6e515f424cb868d07e00411b27fbc; version=5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 <d3b2d2820a005e43855fa71b80c4a4b194201c60

Published CVSS scores

7.8LinuxCVSS: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

T1068Exploitation for Privilege Escalation

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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