How severe is CVE-2020-24336?

CVE-2020-24336 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-24336 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 59% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-24336?

CVE-2020-24336 primarily affects Contiki-ng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-24336?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-24336 published?

CVE-2020-24336 was published on 2020-12-11 and last updated on 2026-06-17.

CVE-2020-24336

CVE-2020-24336 is a critical-severity vulnerability in Contiki-ng with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 59% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 59% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Contiki-ng
Published: 2020-12-11
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-24336?: 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.
How severe is CVE-2020-24336?: CVE-2020-24336 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-24336 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 59% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-24336?: CVE-2020-24336 primarily affects Contiki-ng. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-24336?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-24336 published?: CVE-2020-24336 was published on 2020-12-11 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:*
cpe:2.3:o:contiki-os:contiki:*:*:*:*:*:*:*:*

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