Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

Sabeer_Ali_2389's avatar
Sabeer_Ali_2389
Icon for Altostratus rankAltostratus
Mar 21, 2016

BAD Request - Invalid verb , HTTP Error 400. The request verb is invalid

Sometime we are getting below error while accessing the URL BAD Request - Invalid verb , HTTP Error 400. The request verb is invalid   Web server is IIS server , AS per Microsoft it is happ...
application delivery
LTM
Yann_Desmarest's avatar
Yann_Desmarest
Icon for Cirrus rankCirrus
Mar 21, 2016

Hello,

 

It looks like it's related to the client app. If you add custom rules on the F5 LB, you may also impact the url before sending it to the server.

 

Check your irules, then check the client side.