CVE-2020-17439

HIGHNVD 8.38.3—
EchelonGraph scoreMEDIUM confidence

Score 8.3 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.3EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3.2%CVSS: 8.3Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

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 v3
8.3
EG Score
8.3HIGHmedium confidence
EG Risk
43
EG Risk 43/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity83% × 45%
Exploitation3% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
3.2%
EPSS %ILE
87th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

December 11, 2020

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Sep 6, 2026
No fix on record yet. Sources: cisa, cert.
cert

VU#815128 - Embedded TCP/IP stacks have memory corruption vulnerabilities

https://www.kb.cert.org/vuls/id/815128
cisa

Multiple Embedded TCP/IP Stacks | CISA

https://us-cert.cisa.gov/ics/advisories/icsa-20-343-01

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 165 total refreshes for this CVE.

  1. 2026-10-05 17:39 UTCEPSS rescore
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  1. 2026-09-08 21:56 UTCEPSS rescore
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  46. 2026-07-23 01:50 UTCEG score recompute
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  48. 2026-07-22 14:05 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2020-17439?
CVE-2020-17439 is a high vulnerability published on December 11, 2020. 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…
When was CVE-2020-17439 disclosed?
CVE-2020-17439 was first published on December 11, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-17439 actively exploited?
CVE-2020-17439 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3.2% probability of exploitation in the next 30 days (87th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2020-17439?
CVE-2020-17439 has a CVSS v3 base score of 8.3 (NVD).
How do I remediate CVE-2020-17439?
No fix for CVE-2020-17439 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

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