CVE-2021-21257: contiki-ng Out-of-bounds Write

Vulnerability summary

CVE-2021-21257 is a high (CVSS 8.2) Out-of-bounds Write vulnerability in contiki-ng. EPSS estimates a 1.09% chance of exploitation in the next 30 days, higher than 65% of scored vulnerabilities.

Timeline

1. 18-06-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

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.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.