Bug ID 761565: ASM BD core when custom captcha page configured size more than 45K with %ASM.captcha.support_id% placeholder is at the end

Last Modified: Jan 20, 2023

Bug Tracker

Affected Product:  See more info
BIG-IP ASM(all modules)

Known Affected Versions:
13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,,,,, 13.1.4,, 13.1.5,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,,,, 14.1.3,, 14.1.4,,,,,,, 14.1.5,,,, 15.1.0,,,,,, 15.1.1, 15.1.2,, 15.1.3,, 15.1.4,, 15.1.5,, 15.1.6,, 15.1.7, 15.1.8,

Fixed In:

Opened: Mar 18, 2019
Severity: 2-Critical


ASM BD crash when custom captcha page configured size is 45K


There is an ASM BD crash that occurs upon a request protection by CAPTCHA mitigation. If configured for high availability (HA), failover occurs.


- ASM provisioned. - ASM policy attached to a virtual server. - CAPTCHA page size is bigger than 45 KB. - CAPTCHA protection is enabled via brute force or ASM::captcha iRule.


Define CAPTCHA page sizes smaller than 45 KB.

Fix Information

ASM BD core is fixed; BD no longer crashes, even when the CAPTCHA page size is larger than 45 KM.

Behavior Change