PatchTheCVECVE-2020-24336: An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5
CVE-2020-24336 is a critical-severity flaw (CVSS 9.8) affecting contiki-ng, contiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. The code for parsing Type A domain name answers in ip64-dns64.c doesn't verify whether the address in the answer's length is sane. Therefore, when copying an address of an arbitrary length, a buffer overflow can occur. This bug can be exploited whenever NAT64 is enabled.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 59.1% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-120 |
| Published | 2020-12-11 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2020-24336?
contiki-ng: upgrade to newer than 4.5; contiki: upgrade to newer than 3.0. Exact commands for each OS are on this page.
Is CVE-2020-24336 being exploited?
CVE-2020-24336 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2020-24336 affect?
CVE-2020-24336 affects contiki-ng, contiki. Severity is critical (CVSS 9.8). An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. The code for parsing Type A domain name answers in ip64-dns64.c doesn't verify whether the address in the answer's length is sane. Therefore, when copying an address
How urgent is CVE-2020-24336?
Priority 64/100. Critical severity; EPSS top 1%: very likely to be exploited; Remotely exploitable, no login, no user action
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