Read the docs
TI-2021-04380 Aliases CVE-2021-21280

Out-of-bounds write when processing 6LoWPAN extension headers

Priority MEDIUM 44CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

Contiki-NG is an open-source, cross-platform operating system for internet of things devices. It is possible to cause an out-of-bounds write in versions of Contiki-NG prior to 4.6 when transmitting a 6LoWPAN packet with a chain of extension headers. Unfortunately, the written header is not checked to be within the available space, thereby making it possible to write outside the buffer. The problem has been patched in Contiki-NG 4.6. Users can apply the patch for this vulnerability out-of-band as a workaround.

Why it matters now

EPSS 0.01064 64th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed contiki-ng (contiki-ng): 4.6

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
contiki-ngcontiki-ngbefore 4.64.6Patch availableCNA
  • contiki-ng Vendorcontiki-ng Affected before 4.6 Fixed in 4.6 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:*before 4.6Vulnerablecontiki-ng
  • cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:* Versions before 4.6 Vulnerable ·contiki-ng

Remediation

  • Fix · CNA contiki-ng (contiki-ng) Fixed in 4.6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-21280

References

Exploit 1

Patch 1

  • TI-2020-14885 An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. CVSS 3.1CRITICAL 9.8
  • TI-2020-16751 In Contiki 4.5, TCP ISNs are improperly random. CVSS 3.1CRITICAL 9.1
  • TI-2018-16029 contiki-ng version 4 contains a Buffer Overflow vulnerability in AQL (Antelope Query… CVSS 3.1CRITICAL 9.8
  • TI-2018-13749 An issue was discovered in the MQTT server in Contiki-NG before 4.2. CVSS 3.0CRITICAL 10.0
  • TI-2023-14381 Contiki-NG has off-by-one error in Antelope DBMS CVSS 3.1CRITICAL 9.8
  • TI-2023-14839 Contiki-NG missing NULL pointer check in IPv6 neighbor discovery CVSS 3.1CRITICAL 9.8
See all 41 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences