CVE-2021-36710Public exploit

Kernel privilege escalation via user-mapped GDT call gate

Published Jun 8, 2022 · Updated Aug 4, 2024

Incorrect access control in the ToaruOS 1.99.2 kernel allows local users to gain CPL 0 privileges through a user-writable GDT call gate. The kernel's low-address GDT mapping can inherit a user-accessible page-table entry, letting an unprivileged process remap the GDT page and replace its TSS descriptor with a call gate. Local code execution is required; invoking the gate enters kernel privilege and permits the process credentials to be rewritten as root.

CVSS severity8.8
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect access control in the ToaruOS 1.99.2 kernel allows local users to gain CPL 0 privileges through a user-writable GDT call gate. The kernel's low-address GDT mapping can inherit a user-accessible page-table entry, letting an unprivileged process remap the GDT page and replace its TSS descriptor with a call gate. Local code execution is required; invoking the gate enters kernel privilege and permits the process credentials to be rewritten as root.

The record

CVE
CVE-2021-36710
Published
Jun 8, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-668, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 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

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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-668Exposure of Resource to Wrong Sphere
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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