CVE-2021-32771
In affected versions it is possible to cause a buffer overflow when copying an IPv6 address prefix in the RPL-Classic implementation in Contiki-NG.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.35%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Contiki-NG is an open-source, cross-platform operating system for IoT devices. In affected versions it is possible to cause a buffer overflow when copying an IPv6 address prefix in the RPL-Classic implementation in Contiki-NG. In order to trigger the vulnerability, the Contiki-NG system must have joined an RPL DODAG. After that, an attacker can send a DAO packet with a Target option that contains a prefix length larger than 128 bits. The problem was fixed after the release of Contiki-NG 4.7. Users unable to upgrade may apply the patch in Contiki-NG PR #1615.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.35% probability · 71th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-120
- Affected
- contiki-ng/contiki-ng
- Source
- security-advisories@github.com
EPSS 1.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/contiki-ng/contiki-ng/pull/1615Patch, Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/pull/1615/commits/587ae59956e00316fd44fd7072ac3a6a07b4b20fPatch, Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/releases/tag/release%2Fv4.8Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-jqjf-v7v9-xp6wThird Party Advisory
- https://github.com/contiki-ng/contiki-ng/pull/1615Patch, Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/pull/1615/commits/587ae59956e00316fd44fd7072ac3a6a07b4b20fPatch, Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/releases/tag/release%2Fv4.8Third Party Advisory
- https://github.com/contiki-ng/contiki-ng/security/advisories/GHSA-jqjf-v7v9-xp6wThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.