CVE-2024-21646Network attack vector

Remote code execution via wrapped binary allocation

Published Jan 9, 2024 · Updated Jun 16, 2025

Memory corruption in Microsoft Azure uAMQP C before 2024-01-01 allows remote authenticated users to execute code through malformed AMQP data. In internal_decoder_decode_bytes, an untrusted binary length plus one can wrap to zero, while failed-state processing can free the same allocation twice. Exploitation requires a compromised Azure account able to send malformed IoT Hub payloads, an allocation failure or protocol violation, and control sufficient to overwrite code space.

CVSS severity6.0
Medium
EPSS probability5.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Microsoft Azure uAMQP C before 2024-01-01 allows remote authenticated users to execute code through malformed AMQP data. In internal_decoder_decode_bytes, an untrusted binary length plus one can wrap to zero, while failed-state processing can free the same allocation twice. Exploitation requires a compromised Azure account able to send malformed IoT Hub payloads, an allocation failure or protocol violation, and control sufficient to overwrite code space.

The record

CVE
CVE-2024-21646
Published
Jan 9, 2024
Updated
Jun 16, 2025
Vendor
Microsoft
Product
Azure uAMQP C
Classifications
CWE-94, CWE-190, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jan 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2024-01-01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Microsoft · Azure uAMQP Cversion=< 2024-01-01

Published CVSS scores

6.0GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:L
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-190Integer Overflow or Wraparound
T1203Exploitation for Client Execution

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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