CVE-2021-27080Public exploit

Kernel code execution via uninitialized mqueue inode

Published Mar 11, 2021 · Updated Aug 19, 2026

Kernel code execution in Microsoft Azure Sphere 21.01 allows local users to run unsigned code via crafted message-queue syscalls. The custom kernel's mqueue_alloc_inode function uses kmalloc without calling inode_init_once, leaving i_lru pointers attacker-controlled after heap grooming. Creating and destroying an IPC namespace, or opening a message queue with oversized attributes, reaches the flaw and grants kernel-level execution.

CVSS severity9.3
Critical
EPSS probability1.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kernel code execution in Microsoft Azure Sphere 21.01 allows local users to run unsigned code via crafted message-queue syscalls. The custom kernel's mqueue_alloc_inode function uses kmalloc without calling inode_init_once, leaving i_lru pointers attacker-controlled after heap grooming. Creating and destroying an IPC namespace, or opening a message queue with oversized attributes, reaches the flaw and grants kernel-level execution.

The record

CVE
CVE-2021-27080
Published
Mar 11, 2021
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Azure Sphere
Classifications
CWE-457, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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=-

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Azure Sphereversion=-

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
9.3Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/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 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 exploitPublished

Weakness, pattern, technique

CWE-457Use of Uninitialized Variable
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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