{"cve":"CVE-2020-17439","nvd":{"published":"2020-12-11T23:15:12.857","modified":"2026-06-17T02:58:56.083","status":"Modified","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L","score":8.3},"cwes":["CWE-20"],"references":["https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01","https://www.kb.cert.org/vuls/id/815128","https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01","https://www.kb.cert.org/vuls/id/815128"],"products":["uip_project:uip"],"source":"nvd","synced_at":"2026-10-19T21:12:09.559580076+00:00"},"epss":{"cve":"CVE-2020-17439","score":0.03183,"percentile":0.88077,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}