BugZero | F5 BugID 993269 - DoS timestamp cookies are incompatible with FastL4...

F5 - Defect ID: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

F5 - Defect ID: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

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: Advanced Firewall Manager

Description

Symptoms

Using DoS timestamp cookies together with a FastL4 profile with the timestamp rewrite option enabled might lead to traffic failures. DoS timestamp cookies might also lead to problems with traffic generated by the Linux host.

Impact

Traffic is dropped due to incorrect timestamps.

Conditions

-- DoS timestamp cookies are enabled, and either of the following: -- FastL4 profile with the timestamp rewrite option enabled. -- Traffic originating from Linux host.

Workaround

Disable timestamp cookies on the affected VLAN.

Fix Information

None

Change history

Links

Original Vendor Announcement

Relevant Products

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Affected versions:15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 16.0.0, 16.0.0.1, 16.0.1, 16.0.1.1, 16.0.1.2, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5

Fixed versions: 17.0.0, 16.1.4, 15.1.9

Relevant Products

Click on a version to see all relevant bugs

Fixed versions: 17.0.0, 16.1.4, 15.1.9

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F5 - Defect ID: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

F5 - Defect ID: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

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: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

F5 - Defect ID: 993269

DoS timestamp cookies are incompatible with FastL4 TCP timestamp rewrite option

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