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Fencer Vulns
medium 5.3

CVE-2020-17470 json

An issue was discovered in FNET through 4.6.4.

published 2020-12-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-9422

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

An issue was discovered in FNET through 4.6.4. The code that initializes the DNS client interface structure does not set sufficiently random transaction IDs (they are always set to 1 in _fnet_dns_poll in fnet_dns.c). This significantly simplifies DNS cache poisoning attacks.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-20-343-01 updated cvss 4.0

Multiple Embedded TCP/IP Stacks

  • multiple open source FNET 4.6.3 multiple open source Nut/Net <= 5.1 multiple open source open-iscsi <= 2.1.12 multiple open source picoTCP (EOL) <= 1.7.0 multiple open source picoTCP-NG <= 1.7.0 multiple open source uIP (EOL) <= 1.0
    +2 more products
    multiple open source uIP-Contiki-NG <= 4.5 multiple open source uIP-Contiki-OS (end-of-life [EOL]) <= 3.0
    affected: vendor fix yanzi.dev

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

2.10% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-330 Use of Insufficiently Random Values

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.