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Vulnerability record · CVE-2020-17439 · published 11 December 2020

CVE-2020-17439: Uip project uip improper input validation vulnerability

Uip Project · Uip

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.

8.3 CVSS 3.1 High EPSS 3.2% · top 12.4% CWE-20 · Improper input validation
8.3CVSS 3.1 base score, v2 7.5
3.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2020-17439), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.