Security readout for executives and security teams
Plain-English summary
This is a critical Zephyr RTOS MQTT parsing flaw. A malformed MQTT packet length can corrupt memory and may allow remote code execution in affected firmware. Business urgency depends on whether products embed Zephyr 2.2.0 or later and process untrusted MQTT traffic.
Executive priority
Treat as high-priority where Zephyr-based products parse MQTT across trust boundaries. Prioritize externally reachable or safety-sensitive devices first. If no Zephyr MQTT usage exists, residual risk is much lower but should be documented.
Technical view
CVE-2020-10062 is a CWE-193 off-by-one error in Zephyr's MQTT packet length decoder, tracked as NCC-ZEP-031. The CVSS 3.1 vector is network-reachable, unauthenticated, no user interaction, high complexity, scope changed, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely in embedded or IoT firmware using Zephyr 2.2.0 or later with MQTT packet parsing reachable from untrusted networks. The provided evidence names Zephyr only, not downstream device models or vendors.
Exploitation context
The source bundle does not show CISA KEV listing, active exploitation, or a public exploit. The risk remains serious because the flaw is remotely reachable and can lead to memory corruption and possible code execution when vulnerable MQTT parsing is exposed.
Researcher notes
Evidence is strong for the root cause, affected project, CVSS severity, and possible RCE impact. Evidence is incomplete for downstream products, exploit availability, and universal fixed release boundaries, so validation should rely on vendor advisories and firmware provenance.
Mitigation direction
- Inventory firmware and products that embed Zephyr 2.2.0 or later.
- Identify deployments where MQTT traffic reaches Zephyr-based devices from untrusted networks.
- Apply Zephyr or device-vendor updates that include the MQTT decoder fix.
- Restrict MQTT exposure to trusted networks while updates are planned.
- Check current Zephyr security guidance before release or deployment decisions.
Validation and detection
- Review SBOMs, build manifests, and source trees for Zephyr and MQTT usage.
- Compare deployed firmware against the referenced Zephyr security advisory and fix commit.
- Map MQTT broker, client, and network paths to affected devices.
- Confirm updated firmware no longer contains the vulnerable decoder code.
- Document any compensating network controls for devices awaiting firmware updates.
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-193: 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-2020-10062 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://zephyrprojectsec.atlassian.net/browse/ZEPSEC-84CVE reference · x_refsource_MISC
- https://docs.zephyrproject.org/latest/security/vulnerabilities.html#cve-2020-10062CVE reference · x_refsource_MISC
- https://github.com/zephyrproject-rtos/zephyr/pull/23821/commits/11b7a37d9a0b438270421b224221d91929843de4CVE reference · x_refsource_MISC
- https://research.nccgroup.com/2020/05/26/research-report-zephyr-and-mcuboot-security-assessmentCVE 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.
Off-by-one Error
Off-by-one Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.