Bug ID 1021201: JSON parser is not fully UTF-8 compliant

Last Modified: Apr 28, 2025

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

Known Affected Versions:
15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 15.1.10.5, 15.1.10.6, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1

Opened: May 25, 2021

Severity: 3-Major

Symptoms

JSON parser's character set does not include support for UTF-8 characters and that can result in 'Malformed JSON data' violation when processing requests containing those characters in JSON data.

Impact

Requests are blocked.

Conditions

Requests contain unsupported UTF-8 characters, such as emoji characters, in JSON payload.

Workaround

The System Variable 'relax_unicode_in_json' can be utilized to ignore what JSON identifies as malformed characters when it encounters such unsupported characters. (1) Enable 'relax_unicode_in_json' through CLI: # /usr/share/ts/bin/add_del_internal add relax_unicode_in_json 1 (2) Restart ASM to ensure changes take effect: # bigstart restart asm

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips