CVE-2026-20177

MEDIUM 5.3 ALL-YEARS

Published 2026-08-19 · Last modified 2026-08-20 · cisco · NVD: Awaiting Analysis

A vulnerability in the handling of management plane packets by Cisco Industrial Ethernet (IE) 1000 Series Switches could allow an unauthenticated, remote attacker to cause the device manager, SSH, or API to become inaccessible.This vulnerability is due to insufficient protection against management plane flooding attacks. An attacker could exploit this vulnerability by sending a high rate of ICMP, SSH, or HTTP traffic to an affected device. A successful exploit could allow the attacker to cause the CPU of the device to increase, resulting in a denial of service (DoS) condition on the device manager web GUI, SSH, or API. Data traffic through the device is not affected.

LIMITED SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 43rd percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

5.3CVSS 3.1 · MEDIUM · CNA

ConfidentialityNone
IntegrityNone
AvailabilityLow

What an attacker needs

✓Access: Reachable over the network — no local access needed
✓Privileges: No account or privileges required
✓User interaction: No user interaction needed
✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Cisco

Products Cisco Industrial Ethernet Switches

Weakness (CWE)

CWE-770: Allocation of Resources Without Limits or Throttling

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References and research data (JSON)

All CVSS metrics

MEDIUM 5.3 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
MEDIUM 5.3 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

Advisories

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-62559 ADVISORYEUVD · EUVD-2026-62559

Technical & other

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ie1k-uxq86LnxCVE record · cisco · Updated 2026-08-19T16:16:50.507Z
NVD · CVE-2026-20177 · Updated 2026-08-20T16:17:20.400

Sources: NVD · CVE.org · All sources and attribution · EPSS