BugZero | Cisco BugID CSCws53690 - SST:17.12.6a->17.18.2 ISSU, AP disjoin after activ...

Cisco - Defect ID: CSCws53690

SST:17.12.6a->17.18.2 ISSU, AP disjoin after active -> standby

Cisco - Defect ID: CSCws53690

SST:17.12.6a->17.18.2 ISSU, AP disjoin after active -> standby

Last updated on April 30th, 2026

BugZero Risk Score
7.8 High

Overall: 7.8

Severity: 8.2

Lifecycle: 9.1

Popularity: 4.6

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Bug Details

Views: 1

Description

Symptom

AP disjoins and associate with image upgrade after active -> standby during ISSU 17.12.x -> 17.18.1/17.18.2 Direct ISSU upgrade from 17.12 to 17.18.2 will result in AP reload after 17.18.2 ISSU upgrade with approximate downtime of ~5 minutes (may depend on the network traffic and congestion).

Conditions

This is applicable only for ISSU upgrades.

Workaround

ISSU from 17.12.X to 17.18.2 requires N+1 ISSU upgrade (17.12.x -> 17.15.4d -> 17.18.2). Intermediate upgrade should be done only from 17.15.4d & later. If you are on 17.15.x release, ISSU upgrade from 17.15.x to 17.18.2 will not be impacted by CSCws53690

Further Problem Description

Change history

2025-12-24 Added: 17.18.2

Relevant Products

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Affected versions:17.18.2

Fixed versions: 17.15.1, 17.15.1a, 17.15.1b, 17.15.1w, 17.15.1x, 17.15.1y, 17.15.1z, 17.15.2, 17.15.2a, 17.15.2b, 17.15.2c, 17.15.3, 17.15.3a, 17.15.3b, 17.15.4, 17.15.4a, 17.15.4b, 17.15.4c, 17.15.4d, 17.15.4s1, 17.15.5, 17.15.5a, 17.16.1, 17.16.1a, 17.17.1, 17.18.3, 17.18.3a

Relevant Products

Click on a version to see all relevant bugs

Affected versions:17.18.2

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Cisco - Defect ID: CSCws53690

SST:17.12.6a->17.18.2 ISSU, AP disjoin after active -> standby

Cisco - Defect ID: CSCws53690

SST:17.12.6a->17.18.2 ISSU, AP disjoin after active -> standby

Last updated on April 30th, 2026

BugZero Risk Score7.8 High

Bug Details

Symptom

Conditions

Workaround

Further Problem Description

Top Cisco Defects

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BugZero Risk Score
7.8 High