CVE-2020-36558

Local kernel crash via VT_RESIZEX race

Published Jul 21, 2022 · Updated Aug 4, 2024

A race condition in the Linux kernel before 5.5.7 allows local users to cause a service crash via the VT_RESIZEX ioctl. The VT_RESIZEX handler can access vc_cons[i].d after a concurrent operation has set that pointer to NULL, triggering a NULL pointer dereference and general protection fault. Exploitation requires local access and a race; the documented consequence is kernel availability loss without confidentiality or integrity impact.

CVSS severity5.1
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in the Linux kernel before 5.5.7 allows local users to cause a service crash via the VT_RESIZEX ioctl. The VT_RESIZEX handler can access vc_cons[i].d after a concurrent operation has set that pointer to NULL, triggering a NULL pointer dereference and general protection fault. Exploitation requires local access and a race; the documented consequence is kernel availability loss without confidentiality or integrity impact.

The record

CVE
CVE-2020-36558
Published
Jul 21, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 21, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.1UbuntuCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/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

T1499Endpoint Denial of Service

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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