No exploitation reportedFix available

CVE-2020-17355

Q: Is CVE-2020-17355 actively exploited?

Active exploitation of CVE-2020-17355 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-17355?

CVE-2020-17355 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2020-10-21
Fixed in4.24.2f · 4.23.5m · 4.22.7m · 4.21.12m

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Arista EOS before 4.21.12M, 4.22.x before 4.22.7M, 4.23.x before 4.23.5M, and 4.24.x before 4.24.2F allows remote attackers to cause a denial of service (restart of agents) by crafting a malformed DHCP packet which leads to an incorrect route being installed.

Timeline

dates in UTC

2020-10-2122:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-17355?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-17355?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Arista eos

Branch	Affected	Fixed in	Source
4.24	≥ 4.24.0, < 4.24.2f	4.24.2f	NVD
4.23	≥ 4.23, < 4.23.5m	4.23.5m	NVD
4.22	≥ 4.22, < 4.22.7m	4.22.7m	NVD
4.21	≥ 4.21.0, < 4.21.12m	4.21.12m	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Arista eos to 4.24.2f · 4.23.5m · 4.22.7m · 4.21.12m

Advisories and patches

www.arista.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
FIRST EPSSEPSS score1.2 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2020-10-21
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-17355?

Is CVE-2020-17355 actively exploited?

Active exploitation of CVE-2020-17355 has not been confirmed. Its EPSS score was 1.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-17355?

CVE-2020-17355 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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