Skip to content
KSEF-BUS-163 SECURITY Error KSeF Guard Only

Control characters in invoice text fields

Znaki sterujące w polach tekstowych faktury

Problem

A text field on the invoice contains a prohibited control character (invisible special character). Such characters can cause issues during KSeF processing.

How to Fix

Check item descriptions and other text fields — remove invisible special characters. The only allowed special characters are: tab, newline, and carriage return.

Source Reference

KSeF Guard security guard (XML 1.0 control-character range, W3C XML 1.0 §2.2)

View source

Source Quote

“Invoice text fields must not contain ASCII control characters (0x00-0x1F) except TAB, CR, LF.”
Description SHA-256: 8787ee5409ac…

Justification

FORMAT

Legal Basis Chain

1

W3C XML 1.0 — Char production

W3C XML 1.0 — produkcja Char

“Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF] /* any Unicode character, excluding the surrogate blocks, FFFE, and FFFF. */”
W3C XML 1.0, §2.2 Characters