Security readout for executives and security teams
Plain-English summary
Contiki-NG IoT devices before version 4.5 can overflow memory while processing certain RPL source-routing packets. An attacker with network reachability to an affected RPL deployment could cause serious availability impact and limited confidentiality or integrity impact. The public bundle says the issue is patched in Contiki-NG 4.5.
Executive priority
Treat this as a high-priority embedded systems patching issue where Contiki-NG is present. The main business risk is disruption of IoT devices or low-power mesh networks. Urgency is highest for exposed or operationally critical RPL deployments.
Technical view
CVE-2021-21282 is a CWE-120 buffer overflow in Contiki-NG RPL source routing header processing. It affects Contiki-NG versions before 4.5 when either bundled RPL implementation is used in source-routing mode. CVSS 3.1 is 8.6: network, low complexity, no privileges, no user interaction, unchanged scope.
Likely exposure
Exposure is likely limited to IoT products or firmware built on Contiki-NG before 4.5 and configured to use RPL source routing. Organizations may need vendor firmware bills of materials or supplier confirmation to identify affected embedded deployments.
Exploitation context
The source bundle does not indicate CISA KEV listing or active exploitation. The CVSS vector shows the bug is network-reachable, requires no authentication, and mainly threatens availability. Public sources provided do not establish exploit maturity beyond the vulnerability description and patch reference.
Researcher notes
Key evidence is narrow: affected product is Contiki-NG before 4.5, specifically RPL source-routing mode. Do not generalize to all IoT devices or all RPL stacks. The available bundle names a patch and pull request but does not provide active exploitation evidence.
Mitigation direction
- Upgrade affected Contiki-NG deployments to version 4.5 or later.
- Apply the vendor-referenced out-of-band patch where upgrade is not immediately possible.
- Confirm whether deployed firmware uses Contiki-NG RPL source-routing mode.
- Ask device vendors for fixed firmware if Contiki-NG is embedded.
- Limit untrusted network reachability to affected IoT/RPL networks where feasible.
Validation and detection
- Inventory IoT firmware for Contiki-NG versions before 4.5.
- Confirm whether either Contiki-NG RPL implementation runs in source-routing mode.
- Verify the 4.5 fix or vendor patch is present in deployed firmware.
- Review vendor advisories or SBOMs for CVE-2021-21282 applicability.
- Monitor affected networks for unexplained device crashes or resets.
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 lookupCVE-2021-21282 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
- 8.6 (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: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:L/PR:N/UI:N/S:U/C:L/I:L/A:H3.94.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-6xf2-77gf-fgjxCVE reference · x_refsource_CONFIRM
- https://github.com/contiki-ng/contiki-ng/pull/1183CVE 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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.