CVE-2021-45402Public exploit

Kernel-address disclosure via stale mov32 bounds

Published Feb 11, 2022 · Updated Aug 4, 2024

Improper bounds tracking in the Linux kernel through 5.16-rc5 allows local users to disclose kernel pointer addresses via eBPF mov32 operations. The check_alu_op() verifier path leaves incorrect bounds after a 32-bit register move, allowing pointer-derived arithmetic to become an unknown scalar and be exported through a BPF map. Loading crafted BPF bytecode with low local privileges is sufficient; the demonstrated consequence is address disclosure, not data modification or service interruption.

CVSS severity5.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper bounds tracking in the Linux kernel through 5.16-rc5 allows local users to disclose kernel pointer addresses via eBPF mov32 operations. The check_alu_op() verifier path leaves incorrect bounds after a 32-bit register move, allowing pointer-derived arithmetic to become an unknown scalar and be exported through a BPF map. Loading crafted BPF bytecode with low local privileges is sufficient; the demonstrated consequence is address disclosure, not data modification or service interruption.

The record

CVE
CVE-2021-45402
Published
Feb 11, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-668, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1005Data from Local System

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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