CVE-2021-21257 Out-of-bounds write in RPL-Classic and RPL-Lite
Attackers can trigger out-of-bounds writes via crafted RPL packets in Contiki-NG, potentially leading to code execution or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-21257?
CVE-2021-21257 is a high-severity memory corruption vulnerability in contiki-ng, published on 18 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-787
Which versions are affected by CVE-2021-21257?
It affects 1 product.
Products include Contiki-Ng Contiki-Ng.
How do I fix CVE-2021-21257?
No fix has been published for CVE-2021-21257 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-21257 being exploited?
There is no known exploitation of CVE-2021-21257 in the wild and no public exploit code.