How severe is CVE-2020-17467?

CVE-2020-17467 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2020-17467 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-17467?

CVE-2020-17467 affects Butok Fnet. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-17467?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-17467 published?

CVE-2020-17467 was published on 2020-12-11 and last updated on 2026-06-17.

CVE-2020-17467

CVE-2020-17467 is a critical-severity vulnerability in Butok Fnet with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Butok Fnet
Published: 2020-12-11
Last modified: 2026-06-17

Description

An issue was discovered in FNET through 4.6.4. The code for processing the hostname from an LLMNR request doesn't check for '\0' termination. Therefore, the deduced length of the hostname doesn't reflect the correct length of the actual data. This may lead to Information Disclosure in _fnet_llmnr_poll in fnet_llmnr.c during a response to a malicious request of the DNS class IN.

Frequently asked questions

What is CVE-2020-17467?: An issue was discovered in FNET through 4.6.4. The code for processing the hostname from an LLMNR request doesn't check for '\0' termination. Therefore, the deduced length of the hostname doesn't reflect the correct length of the actual data. This may lead to Information Disclosure in _fnet_llmnr_poll in fnet_llmnr.c during a response to a malicious request of the DNS class IN.
How severe is CVE-2020-17467?: CVE-2020-17467 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2020-17467 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-17467?: CVE-2020-17467 affects Butok Fnet. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-17467?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-17467 published?: CVE-2020-17467 was published on 2020-12-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:butok:fnet:*:*:*:*:*:*:*:*

More vulnerabilities in Butok Fnet

CVE-2020-27633 — Critical (CVSS 9.1): In FNET 4.6.3, TCP ISNs are improperly random.
CVE-2020-24383 — Critical (CVSS 9.1): An issue was discovered in FNET through 4.6.4. The code for processing resource records in mDNS queries doesn't check…
CVE-2020-17469 — High (CVSS 7.5): An issue was discovered in FNET through 4.6.4. The code for IPv6 fragment reassembly tries to access a previous…
CVE-2020-17468 — High (CVSS 7.5): An issue was discovered in FNET through 4.6.4. The code for processing the hop-by-hop header (in the IPv6 extension…
CVE-2020-17470 — Medium (CVSS 5.3): An issue was discovered in FNET through 4.6.4. The code that initializes the DNS client interface structure does not…

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