Security readout for executives and security teams
Plain-English summary
RIOT OS 2020.01.1 has an integer wrap-around flaw in its calloc memory allocation function. In affected embedded or IoT devices, this can cause crashes and may allow remote code injection or execution. The business risk depends on whether vulnerable RIOT-based firmware is deployed in reachable devices.
Executive priority
Treat this as a high-priority embedded systems exposure review, especially for internet-connected or operational devices. Do not assume exposure from product name alone; confirm whether deployed firmware actually uses RIOT OS 2020.01.1.
Technical view
CVE-2021-27427 is a CWE-190 integer overflow or wraparound in RIOT OS 2020.01.1 calloc implementation. The CVSS 3.1 score is 7.3 with network attack vector, low complexity, no privileges, and no user interaction. Sources describe arbitrary memory allocation causing unexpected behavior, including crash or remote code injection/execution.
Likely exposure
Exposure is most likely in embedded, IoT, or operational devices running firmware based on RIOT OS 2020.01.1. The bundle does not identify other affected versions or specific device vendors, so teams should verify through firmware SBOMs, vendor notices, and source manifests.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates the issue may be network-reachable without authentication or user interaction, but exploitability in practice depends on how calloc is reached in each firmware application.
Researcher notes
Evidence is clear for RIOT OS 2020.01.1 and the vulnerable calloc behavior, but the bundle does not provide a fixed version, patch commit, affected downstream devices, or exploitation evidence. Validation should focus on firmware provenance and reachable code paths.
Mitigation direction
- Inventory products and firmware that embed RIOT OS 2020.01.1.
- Check RIOT OS and CISA guidance for fixed releases or vendor-approved mitigations.
- Prioritize network isolation for affected embedded devices until remediation is confirmed.
- Ask device vendors whether their firmware includes the vulnerable calloc implementation.
- Monitor affected devices for crashes, memory faults, or unexpected resets.
Validation and detection
- Confirm RIOT OS version through firmware SBOMs, source manifests, or vendor attestations.
- Compare deployed firmware against RIOT OS 2020.01.1 usage records.
- Review whether network-exposed services can reach RIOT memory allocation paths.
- Check logs and telemetry for unexplained crashes or abnormal memory behavior.
- Document any compensating controls around affected device network access.
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-190: 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-2021-27427 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
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/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:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisa.gov/uscert/ics/advisories/icsa-21-119-04CVE reference · x_refsource_CONFIRM
- https://github.com/RIOT-OS/RIOTCVE reference · x_refsource_CONFIRM
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.
Integer Overflow or Wraparound
Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.