CVE-2020-17439

Name: CVE-2020-17439
Creator: NVD / NIST
Published: 2020-12-11T23:15:12.857+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.3/10EPSS 3.15%

Last modified Jun 17, 2026

CVE-2020-17439 is a high-severity vulnerability rated 8.3/10 on the CVSS scale. An issue was discovered in uIP 1.0, as used in Contiki 3.0 and other products. The code that parses incoming DNS packets does not validate that the incoming DNS replies match outgoing DNS queries in newdata() in resolv.c. EPSS estimates a 3.15% chance of exploitation in the next 30 days.

Description

An issue was discovered in uIP 1.0, as used in Contiki 3.0 and other products. The code that parses incoming DNS packets does not validate that the incoming DNS replies match outgoing DNS queries in newdata() in resolv.c. Also, arbitrary DNS replies are parsed if there was any outgoing DNS query with a transaction ID that matches the transaction ID of an incoming reply. Provided that the default DNS cache is quite small (only four records) and that the transaction ID has a very limited set of values that is quite easy to guess, this can lead to DNS cache poisoning.

Metrics

CVSS 3.1

8.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

EPSS Probability

3.15%

86.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Uip Project	Uip	1.0

References

https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01Third Party Advisory, US Government Resource
https://www.kb.cert.org/vuls/id/815128Third Party Advisory, US Government Resource
https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01Third Party Advisory, US Government Resource
https://www.kb.cert.org/vuls/id/815128Third Party Advisory, US Government Resource

Timeline

Published: Dec 11, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-17439?

How severe is CVE-2020-17439?

CVE-2020-17439 has a CVSS score of 8.3/10 (HIGH severity). The EPSS model estimates a 3.15% probability of exploitation in the next 30 days.

How do I fix CVE-2020-17439?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-17439?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST