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

Forum Discussion

emile's avatar
emile
Icon for Nimbostratus rankNimbostratus
Oct 25, 2023

POST requests lost between two vs intermittently

Hi, Since we upgraded our BIG-IP F5 from 14.1.4.6 to 17.1.0.2, we encountered a loss of POST requests between virtualserver and our backend. This is always the same request which is blocked. Firs...
application delivery
emile's avatar
emile
Icon for Nimbostratus rankNimbostratus
Oct 26, 2023

Hi Enes,

Thanks a lot for your answer. 
I've tried to pass the value of tmm.http.rfc.allowwsheadername to disable in v14.1.4.6 and I didn't manage to reproduce the issue. 

To be sure, I'll enable the setting concerned in v17 and see if the problem disappears.

 

emile's avatar
emile
Icon for Nimbostratus rankNimbostratus
Oct 26, 2023

Unfortunately, the problem persists with the Allow Space Header Name enabled.

  • emile's avatar
    emile
    Icon for Nimbostratus rankNimbostratus
    Nov 16, 2023

    We can confirm that the bug was introduced in v16, we upgraded to v15 and the bug disappeared. We looked for similar issues that appeared in v16 but didn't find anything conclusive. any help would be most welcome.