Security readout for executives and security teams
Plain-English summary
This is a critical flaw in Zephyr's MQTT message handling. A vulnerable device that accepts crafted MQTT publish messages could suffer memory corruption, with potential remote code execution. Business risk is highest for connected embedded products using Zephyr 2.2.0 or later with reachable MQTT functionality.
Executive priority
Prioritize this for connected products or operational devices that rely on Zephyr MQTT. It is critical severity with potential remote code execution, but urgency should be tied to whether MQTT is enabled and reachable in deployed firmware.
Technical view
Zephyr MQTT parsing performs insufficient validation of the publish message length field. The reported weakness maps to CWE-120 and CWE-129 and can cause a buffer overflow. CVSS 3.1 is 9.0: network attack vector, no privileges, no user interaction, high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to embedded or IoT systems built on zephyrproject-rtos Zephyr version 2.2.0 and later that include MQTT parsing and accept MQTT publish messages from network peers. Actual exposure depends on product firmware, enabled features, and network reachability.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates remote network reachability but high attack complexity. Treat exploitation as plausible for exposed MQTT-enabled devices, not confirmed in the provided evidence.
Researcher notes
Evidence identifies insufficient publish length validation in Zephyr MQTT parsing, affecting Zephyr 2.2.0 and later. The provided sources include an NCC Group assessment, Zephyr advisory entry, vulnerability documentation, and an upstream commit reference. No exploit activity is established in the bundle.
Mitigation direction
- Identify products and firmware using Zephyr 2.2.0 or later.
- Check Zephyr security guidance and the referenced upstream commit for the supported fix.
- Apply vendor firmware updates when available for affected products.
- Restrict untrusted network access to MQTT-enabled embedded devices.
- Monitor Zephyr and product-vendor advisories for backported fixes.
Validation and detection
- Inventory firmware components for Zephyr and MQTT support.
- Confirm whether MQTT publish messages can reach the device from untrusted networks.
- Compare the firmware source or vendor release notes against the referenced Zephyr fix.
- Review product SBOMs and build manifests for affected Zephyr versions.
- Prioritize validation on internet-facing, field-deployed, or safety-critical devices.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-120: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-129: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-10071 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H2.26Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9CriticalVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://research.nccgroup.com/2020/05/26/research-report-zephyr-and-mcuboot-security-assessmentCVE reference · x_refsource_MISC
- https://zephyrprojectsec.atlassian.net/browse/ZEPSEC-86CVE reference · x_refsource_MISC
- https://docs.zephyrproject.org/latest/security/vulnerabilities.html#cve-2020-10071CVE reference · x_refsource_MISC
- https://github.com/zephyrproject-rtos/zephyr/pull/23821/commits/989c4713ba429aa5105fe476b4d629718f3e6082CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.