CVE-2021-47456

Freed-memory read via final-channel teardown

Published May 22, 2024 · Updated May 11, 2026

Use-after-free in the Linux kernel peak_pci CAN driver allows local users to access freed memory during module removal. On the final channel, peak_pci_remove frees the network device that owns chan and then dereferences chan->pciec_card. Triggering requires local removal of the peak_pci module; the published evidence confirms an eight-byte post-free read but does not establish a reliable further consequence.

CVSS severity8.4
High
EPSS probability0.24%
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 the Linux kernel peak_pci CAN driver allows local users to access freed memory during module removal. On the final channel, peak_pci_remove frees the network device that owns chan and then dereferences chan->pciec_card. Triggering requires local removal of the peak_pci module; the published evidence confirms an eight-byte post-free read but does not establish a reliable further consequence.

The record

CVE
CVE-2021-47456
Published
May 22, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=3.4
  2. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <0e5afdc2315b0737edcf55bede4ee1640d2d464d
  3. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <1248582e47a9f7ce0ecd156c39fc61f8b6aa3699
  4. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <1c616528ba4aeb1125a06b407572ab7b56acae38
  5. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <28f28e4bc3a5e0051faa963f10b778ab38c1db69
  6. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <34914971bb3244db4ce2be44e9438a9b30c56250
  7. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <447d44cd2f67a20b596ede3ca3cd67086dfd9ca9
  8. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <949fe9b35570361bc6ee2652f89a0561b26eec98
  9. Affected versionversion=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <adbda14730aacce41c0d3596415aa39ad63eafd9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.4; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <0e5afdc2315b0737edcf55bede4ee1640d2d464d; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <1248582e47a9f7ce0ecd156c39fc61f8b6aa3699; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <1c616528ba4aeb1125a06b407572ab7b56acae38; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <28f28e4bc3a5e0051faa963f10b778ab38c1db69; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <34914971bb3244db4ce2be44e9438a9b30c56250; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <447d44cd2f67a20b596ede3ca3cd67086dfd9ca9; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <949fe9b35570361bc6ee2652f89a0561b26eec98; version=e6d9c80b7ca1504411ad6d7acdb8683e4ae1c9cd <adbda14730aacce41c0d3596415aa39ad63eafd9
The Linux Kernel Organization · Linux Kernelversion=3.4; version=e6d9c80b7ca1

Published CVSS scores

8.4CISA ADPCVSS:3.1/AV:L/AC:L/PR:N/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
Privilegesunauthenticated
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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