CVE-2021-47670

Kernel use-after-free via post-receive skb dereference

Published Apr 17, 2025 · Updated Aug 5, 2026

Use-after-free in Linux's peak_usb CAN driver allows local users to access freed kernel memory while the driver receives a CAN frame. The receive path calls peak_usb_netif_rx_ni(skb), then reads the aliased can_frame after the skb has been handed off. Reachability requires the peak_usb CAN driver and compatible PEAK USB CAN hardware; the record establishes unsafe memory access but no demonstrated end effect.

CVSS severity7.8
High
EPSS probability0.22%
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's peak_usb CAN driver allows local users to access freed kernel memory while the driver receives a CAN frame. The receive path calls peak_usb_netif_rx_ni(skb), then reads the aliased can_frame after the skb has been handed off. Reachability requires the peak_usb CAN driver and compatible PEAK USB CAN hardware; the record establishes unsafe memory access but no demonstrated end effect.

The record

CVE
CVE-2021-47670
Published
Apr 17, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 17, 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=0a25e1f4f18566b750ebd3ae995af64e23111e63 <50aca891d7a554db0901b245167cd653d73aaa71
  2. Affected versionversion=0a25e1f4f18566b750ebd3ae995af64e23111e63 <5408824636fa0dfedb9ecb0d94abd573131bfbbe
  3. Affected versionversion=0a25e1f4f18566b750ebd3ae995af64e23111e63 <ddd1416f44130377798c1430b76503513b7497c2
  4. Affected versionversion=0a25e1f4f18566b750ebd3ae995af64e23111e63 <ec939c13c3fff2114479769c8380b7f1a54feca9
  5. Affected versionversion=4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0a25e1f4f18566b750ebd3ae995af64e23111e63 <50aca891d7a554db0901b245167cd653d73aaa71; version=0a25e1f4f18566b750ebd3ae995af64e23111e63 <5408824636fa0dfedb9ecb0d94abd573131bfbbe; version=0a25e1f4f18566b750ebd3ae995af64e23111e63 <ddd1416f44130377798c1430b76503513b7497c2; version=0a25e1f4f18566b750ebd3ae995af64e23111e63 <ec939c13c3fff2114479769c8380b7f1a54feca9; version=4.0

Published CVSS scores

7.8CISA ADPCVSS: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.

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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