CVE-2020-35508

Arbitrary privileged-process signals via CLONE_PARENT race

Published Mar 26, 2021 · Updated Aug 4, 2024

Race condition in Linux Kernel 5.12 allows local users to send arbitrary signals to privileged processes through CLONE_PARENT. In copy_process, the kernel reads group_leader->exit_signal before taking tasklist_lock, so a concurrent real-parent exit can change the value during the copy. A low-privileged local account must win this timing race; successful abuse bypasses signal checks and can alter or interrupt a privileged process.

CVSS severity4.5
Medium
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

Race condition in Linux Kernel 5.12 allows local users to send arbitrary signals to privileged processes through CLONE_PARENT. In copy_process, the kernel reads group_leader->exit_signal before taking tasklist_lock, so a concurrent real-parent exit can change the value during the copy. A low-privileged local account must win this timing race; successful abuse bypasses signal checks and can alter or interrupt a privileged process.

The record

CVE
CVE-2020-35508
Published
Mar 26, 2021
Updated
Aug 4, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362, CWE-665, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2021CVE 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?

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  1. Affected versionversion=kernel 5.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=kernel 5.12

Published CVSS scores

4.5NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-665Improper Initialization
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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