CVE-2020-10071Network attack vector

Remote code execution via underflowed payload length

Published Jun 5, 2020 · Updated Sep 17, 2024

Buffer overflow in Zephyr RTOS 2.2.0 MQTT parsing allows remote attackers to execute code through a malformed PUBLISH message. The publish_decode function subtracts the parsed variable-header length from a smaller attacker-declared packet length, underflowing the payload length. The MQTT library must be enabled and process attacker-controlled traffic; exploitation can corrupt device memory or execute code in the firmware context.

CVSS severity9.0
Critical
EPSS probability3.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Zephyr RTOS 2.2.0 MQTT parsing allows remote attackers to execute code through a malformed PUBLISH message. The publish_decode function subtracts the parsed variable-header length from a smaller attacker-declared packet length, underflowing the payload length. The MQTT library must be enabled and process attacker-controlled traffic; exploitation can corrupt device memory or execute code in the firmware context.

The record

CVE
CVE-2020-10071
Published
Jun 5, 2020
Updated
Sep 17, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-120, CWE-129, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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?

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

  1. Affected versionversion=2.2.0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=2.2.0 <unspecified

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.0Zephyr ProjectCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-129Improper Validation of Array Index
T1190Exploit Public-Facing Application

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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