No exploitation reportedFix available

CVE-2020-24336

No exploitation reported by the sources we read.

Published2020-12-11
WeaknessCWE-120

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2020-12-1123:15CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-24336?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-24336?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Contiki-ng

Branch	Affected	Fixed in	Source
4.5	≤ 4.5	no fix published	NVD

Contiki-os contiki

Branch	Affected	Fixed in	Source
3.0	≤ 3.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-20-343-01 CISA8 known affected
Multiple Embedded TCP/IP Stacks
uIP (EOL): Version 1.0 and prior · uIP-Contiki-NG: Version 4.5 and prior · Nut/Net: Version 5.1 and prior · +5 more

Full record on NVD

Fix

Vendor fix CISA ICSA-20-343-01 · 8 productsAdditional vendors affected by the reported vulnerabilities have also released security advisories related to their affected products. Those advisories are as follows:

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-120read 2026-10-23
FIRST EPSSEPSS score59.1 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2020-12-11
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-24336?

Is CVE-2020-24336 actively exploited?

Active exploitation of CVE-2020-24336 has not been confirmed. Its EPSS score was 59.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-24336?

CVE-2020-24336 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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