Bug ID 720626: Portal Access: CSS custom properties are supported by server-side CSS parser.

Last Modified: Jul 12, 2023

Affected Product(s):
BIG-IP APM(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,

Fixed In:

Opened: May 17, 2018

Severity: 3-Major


Modern CSS includes custom properties (variables). Portal Access does not support them. When a custom property contains some external URL values, this value cannot be rewritten.


Web application may not work correctly.


CSS file or HTML STYLE element with custom property inside, for example: :root { --iset: image-set(url("/images/image-384.jpg") 1x, url("/images/image-768.jpg") 2x,); } .img { background-image: var(--iset); }


Use iRules to substitute 'var()' function calls in CSS files with the corresponding custom property values.

Fix Information

Now Portal Access supports CSS custom properties in server-side CSS parser.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips