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TI-2021-04359 Aliases CVE-2021-21257

Out-of-bounds write in RPL-Classic and RPL-Lite

Priority LOW 38CWE-787Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Contiki-NG is an open-source, cross-platform operating system for internet of things devices. The RPL-Classic and RPL-Lite implementations in the Contiki-NG operating system versions prior to 4.6 do not validate the address pointer in the RPL source routing header This makes it possible for an attacker to cause out-of-bounds writes with packets injected into the network stack. Specifically, the problem lies in the rpl_ext_header_srh_update function in the two rpl-ext-header.c modules for RPL-Classic and RPL-Lite respectively. The addr_ptr variable is calculated using an unvalidated CMPR field value from the source routing header. An out-of-bounds write can be triggered on line 151 in os/net/routing/rpl-lite/rpl-ext-header.c and line 261 in os/net/routing/rpl-classic/rpl-ext-header.c, which contain the following memcpy call with addr_ptr as destination. The problem has been patched in Contiki-NG 4.6. Users can apply a patch out-of-band as a workaround.

Why it matters now

EPSS 0.01088 65th percentileScored 2026-11-07
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-2021-21257

References

Patch 2

  • 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