BugZero | F5 BugID 550434 - Diameter connection may stall if server closes con...

F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

Last updated on July 18th, 2026

BugZero Risk Score
6.9 Medium

Overall: 6.9

Severity: 7.3

Community: 4.2

Lifecycle: 8.3

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Bug Details

Priority: 3-Major
Status: Verified
Impact Category: Service Provider

Description

Symptoms

Serverside connection stalls. Connection is not torn down and packets are not forwarded to serverside.

Impact

Connection stalls until handshake timeout and then it is reset.

Conditions

Selected pool member closes (via FIN) connection before sending CEA as part of Diameter handshake.

Workaround

none

Fix Information

Serverside diameter connections will be immediately reset if FIN is received before CEA (Capabilities-Exchange-Answer).

Change history

Links

Original Vendor Announcement

Relevant Products

Click on a version to see all relevant bugs

Affected versions:11.5.1, 11.5.1 hf1, 11.5.1 hf2, 11.5.1 hf3, 11.5.1 hf4, 11.5.1 hf5, 11.5.1 hf6, 11.5.1 hf7, 11.5.1 hf8, 11.5.1 hf9, 11.5.1 hf10, 11.5.1 hf11, 11.5.2, 11.5.2 hf1, 11.5.3, 11.5.3 hf1, 11.5.3 hf2, 11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 11.5.6, 11.5.7, 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, 11.6.5.1, 11.6.5.2, 11.6.5.3, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4

Fixed versions: 12.1.0, 12.1.0

Relevant Products

Click on a version to see all relevant bugs

Fixed versions: 12.1.0, 12.1.0

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F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

Last updated on July 18th, 2026

BugZero Risk Score6.9 Medium

Bug Details

Symptoms

Impact

Conditions

Workaround

Fix Information

Links

Top F5 Defects

Ready to prevent the next vendor outage?

F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

F5 - Defect ID: 550434

Diameter connection may stall if server closes connection before CER/CEA handshake completes

Last updated on July 18th, 2026

BugZero Risk Score6.9 Medium

Bug Details

Symptoms

Impact

Conditions

Workaround

Fix Information

Links

Top F5 Defects

Ready to prevent the next vendor outage?

BugZero Risk Score
6.9 Medium

BugZero Risk Score
6.9 Medium