Bug ID 537704: A false RFC violation happens when there are spaces after the content length header

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP ASM(all modules)

Known Affected Versions:
11.5.1, 11.5.2, 11.5.3, 11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Fixed In:

Opened: Aug 05, 2015

Severity: 3-Major


The system issues a false positive "HTTP protocol compliance failed" sub-violation: "Unparsable request content" if there are spaces after the digits in the content length header.


A false positive violation


Spaces after the digits in the content length header


To work around this issue, create an iRule that strips the content length of the trailing spaces.

Fix Information

asm ignores Content length header with trailing whitespaces.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips