BugZero | F5 BugID 756450 - Traffic using route entry that's more specific tha...

F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

Last updated on July 18th, 2026

BugZero Risk Score
8.4 High

Overall: 8.4

Severity: 9.1

Community: 4.2

Lifecycle: 7.0

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Bug Details

Priority: 2-Critical
Status: Verified
Impact Category: Local Traffic Manager

Description

Symptoms

TMM asserts with 'Attempting to free loopback interface'message.

Impact

Traffic disrupted while tmm restarts.

Conditions

- Using blackhole routes. - Have a route entry that is more specific than the existing blackhole route.

Workaround

Use /32 blackhole routes.

Fix Information

TMM no longer cores when using blackhole routes that are less specific than non-blackhole routes.

Change history

Links

Original Vendor Announcement

Relevant Products

Click on a version to see all relevant bugs

Affected versions:11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.0 hf1, 11.6.0 hf2, 11.6.0 hf3, 11.6.0 hf4, 11.6.0 hf5, 11.6.0 hf6, 11.6.0 hf7, 11.6.0 hf8, 11.6.1, 11.6.1 hf1, 11.6.1 hf2, 11.6.2, 11.6.2 hf1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4, 12.1.0, 12.1.0 hf1, 12.1.0 hf2, 12.1.1, 12.1.1 hf1, 12.1.1 hf2, 12.1.2, 12.1.2 hf1, 12.1.2 hf2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 13.0.0, 13.0.0 hf1, 13.0.0 hf2, 13.0.0 hf3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2

Fixed versions: 15.0.0, 14.1.2.3, 13.1.3, 12.1.5, 11.6.5.1

Relevant Products

Click on a version to see all relevant bugs

Fixed versions: 15.0.0, 14.1.2.3, 13.1.3, 12.1.5, 11.6.5.1

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F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

Last updated on July 18th, 2026

BugZero Risk Score8.4 High

Bug Details

Symptoms

Impact

Conditions

Workaround

Fix Information

Links

Top F5 Defects

Ready to prevent the next vendor outage?

F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

F5 - Defect ID: 756450

Traffic using route entry that's more specific than existing blackhole route can cause core

Last updated on July 18th, 2026

BugZero Risk Score8.4 High

Bug Details

Symptoms

Impact

Conditions

Workaround

Fix Information

Links

Top F5 Defects

Ready to prevent the next vendor outage?

BugZero Risk Score
8.4 High

BugZero Risk Score
8.4 High