Security readout for executives and security teams
CVE-2021-3434 is a medium-severity stack buffer overflow in Zephyr’s L2CAP handling. It matters mainly for products using affected Zephyr releases in firmware. The published scoring indicates local attack conditions and high complexity, so this is not presented as an internet-scale emergency. Likely exposure is embedded or connected products built on Zephyr v2.5.0 or v2.6.0 where the affected L2CAP path is present. The source bundle does not identify downstream products, device classes, or configuration requirements beyond the affected Zephyr versions. Handle as a targeted firmware exposure review, not a broad emergency. Prioritize asset identification and vendor confirmation for Zephyr-based products, especially where local wireless attack surface could matter operationally. Mitigation focus: Inventory firmware and SBOMs for Zephyr v2.5.0 or v2.6.0.; Check the Zephyr GitHub advisory for vendor-approved fixed versions or backports.; Ask device vendors whether shipped firmware includes the affected Zephyr code path..
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
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ATT&CK lookup starting points
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CWE-121: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-3434 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
- Medium
- CVSS
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
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:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L1.43.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
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.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.