Security readout for executives and security teams
CVE-2021-3835 is a high-severity heap buffer overflow in Zephyr RTOS’s USB device class. Business risk is concentrated in products or firmware that embed affected Zephyr versions and expose USB device functionality. The provided sources do not identify active exploitation or a specific fixed version. Exposure is most likely in embedded, IoT, industrial, or appliance firmware built on Zephyr v2.6.0 or versions described as >= v2.6.0, where USB device class support is present. Exact downstream product exposure requires SBOM, firmware, or vendor confirmation. Prioritize this for products where Zephyr-based firmware exposes USB functionality in reachable environments. It is high severity, but urgency depends on deployed exposure and vendor patch availability because the bundle does not show active exploitation. Mitigation focus: Review the Zephyr GitHub advisory for vendor-confirmed fixed versions and guidance.; Upgrade affected Zephyr-based firmware to a vendor-supported fixed release when identified.; Disable USB device class functionality where it is not required..
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-122: 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 lookupCVE-2021-3835 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
- High
- CVSS
- 8.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:L/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:A/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H1.66Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.