CVE-2021-32606Public exploit

Local root escalation via unlocked socket-option race

Published May 11, 2021 · Updated Aug 3, 2024

A race condition in Linux kernel 5.11 through 5.12.2 allows local users to escalate privileges to root through CAN ISO-TP sockets. isotp_setsockopt() checks the bound flag without the socket lock, so a concurrent bind can register a CAN receiver before SF_BROADCAST is copied into the socket, causing isotp_release() to skip can_rx_unregister(). Local low-privileged access is required; the demonstrated path also relies on user namespaces, virtual CAN, CAN ISO-TP, and an address leak before overwriting sk_error_report() to run a root ROP chain.

CVSS severity7.8
High
EPSS probability0.43%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in Linux kernel 5.11 through 5.12.2 allows local users to escalate privileges to root through CAN ISO-TP sockets. isotp_setsockopt() checks the bound flag without the socket lock, so a concurrent bind can register a CAN receiver before SF_BROADCAST is copied into the socket, causing isotp_release() to skip can_rx_unregister(). Local low-privileged access is required; the demonstrated path also relies on user namespaces, virtual CAN, CAN ISO-TP, and an address leak before overwriting sk_error_report() to run a root ROP chain.

The record

CVE
CVE-2021-32606
Published
May 11, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.4SUSECVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

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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