gchq/CyberChef

bug(Decode Text): Uncaught Error "Unrecognized CP: undefined"

Closed

#2,494 opened on Jun 4, 2026

View on GitHubContributor guide
 (0 comments) (0 reactions) (0 assignees)JavaScript (3,944 forks)batch import
buggood first issuehelp wanted

Repository metrics

Stars
 (34,843 stars)
PR merge metrics
 (Avg merge 57d 13h) (62 merged PRs in 30d)

Description

To reproduce that use a direct link https://gchq.github.io/CyberChef/#recipe=Decode_text('')&oenc=65001&oeol=VT then as you can see an uncaught error

Decode text - Error in https://gchq.github.io/CyberChef/modules/Encodings.js on line 2.<br><br>Message: Unrecognized CP: undefined

the issue is simple and persists the parameter not validated is have a value or not, it happend with both Encode Text and Decode Text

Contributor guide

Research direction
Add validation for the codepage parameter in the Decode Text and Encode Text operations to prevent the 'Unrecognized CP: undefined' error.
Tech stack
javascript
Domain
frontend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
1
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
None
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
85