CVE-2021-3864Public exploit

Local privilege escalation via incorrect descendant dumpability

Published Aug 26, 2022 · Updated Aug 3, 2024

Improper access control in the Linux Kernel allows local users to escalate privileges by placing core dumps in root-owned directories. In fs/exec.c, begin_new_exec assigns SUID_DUMP_USER after a qualifying SUID program equalizes its real and effective IDs before execve. Exploitation requires a crashable descendant, a relative core_pattern, and an eligible root-SUID path, enabling a privileged file write and code execution.

CVSS severity7.0
High
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in the Linux Kernel allows local users to escalate privileges by placing core dumps in root-owned directories. In fs/exec.c, begin_new_exec assigns SUID_DUMP_USER after a qualifying SUID program equalizes its real and effective IDs before execve. Exploitation requires a crashable descendant, a relative core_pattern, and an eligible root-SUID path, enabling a privileged file write and code execution.

The record

CVE
CVE-2021-3864
Published
Aug 26, 2022
Updated
Aug 3, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-284, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2022CVE 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?

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  1. Affected versionversion=Not Known

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Not Known

Published CVSS scores

7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Red HatCVSS:3.1/AV:L/AC:H/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 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-284Improper Access Control
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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