Security readout for executives and security teams
Plain-English summary
CVE-2021-32771 affects Contiki-NG, an IoT operating system. A malformed RPL-Classic network message can trigger a buffer overflow after a device has joined an RPL DODAG. The issue is rated high because memory corruption may affect confidentiality, integrity, and availability of constrained devices.
Executive priority
Prioritize affected IoT deployments that participate in RPL networks, especially where devices support safety, operations, or sensitive telemetry. This is high severity but not currently evidenced as actively exploited in the provided sources.
Technical view
Affected Contiki-NG versions before 4.8 can overflow a buffer while copying an IPv6 address prefix in RPL-Classic. The vulnerable condition involves a DAO Target option with a prefix length greater than 128 bits after DODAG membership. The vendor fixed it after 4.7; PR #1615 contains the patch.
Likely exposure
Most exposure is in IoT firmware or products built on Contiki-NG before 4.8 that use RPL-Classic and join RPL DODAGs. Generic enterprise systems are unlikely to be directly affected unless they embed or manage such devices.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires network reachability in the relevant RPL context and a device state where it has joined an RPL DODAG, which matches the CVSS high attack complexity.
Researcher notes
Key constraints matter: the vulnerable path is in RPL-Classic, requires DODAG membership, and involves improper handling of an IPv6 prefix length above 128 bits. Evidence supports versions before 4.8 and the PR #1615 patch; no broader product list is provided.
Mitigation direction
- Upgrade Contiki-NG-based builds to version 4.8 or later.
- If upgrade is not possible, apply the vendor patch from PR #1615.
- Confirm device vendors have incorporated the fixed Contiki-NG code.
- Rebuild and redeploy affected firmware after applying the fix.
- Check vendor guidance for product-specific remediation and rollout constraints.
Validation and detection
- Inventory products, firmware, and SBOMs for Contiki-NG usage.
- Identify Contiki-NG versions before 4.8 or forks missing PR #1615.
- Confirm whether RPL-Classic is enabled in affected builds.
- Verify deployed devices can join RPL DODAGs in their operating environment.
- Track remediation evidence from firmware release notes or vendor advisories.
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
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2021-32771 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/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:U/C:H/I:H/A:H2.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-jqjf-v7v9-xp6wCVE reference · x_refsource_CONFIRM
- https://github.com/contiki-ng/contiki-ng/pull/1615CVE reference · x_refsource_MISC
- https://github.com/contiki-ng/contiki-ng/pull/1615/commits/587ae59956e00316fd44fd7072ac3a6a07b4b20fCVE reference · x_refsource_MISC
- https://github.com/contiki-ng/contiki-ng/releases/tag/release%2Fv4.8CVE 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.