Bug Report: Confluence Editor Crash When Pasting Markdown Table with Leading Spaces and Dashes

[Amr Thabit]

Bug Report: Confluence Editor Crash When Pasting Markdown Table with Leading Spaces and Dashes

Summary

Pasting a markdown table with leading spaces and standalone - cell values causes the Confluence editor to freeze (Firefox) or crash with out-of-memory (Chrome).

Environment

• Product: Confluence Cloud
• Browsers: Chrome (crashes), Firefox (freezes, UI unresponsive)
• Editor: New editor (ProseMirror-based)

 | A |
 |---|
 | - |
 | - |

Requirements:

1. Leading space before | on each line
2. Two or more rows with standalone - as cell value

Steps to Reproduce

1. Open any Confluence page in edit mode
2. Copy the text above (preserve leading spaces)
3. Paste into editor (Ctrl+V) using markdown
4. Observe freeze/crash

Observed Behavior

• Chrome: Memory spikes from ~700MB to 6.3GB+, tab crashes with "Aw, Snap!" error (Error code: Out of Memory)
• Firefox: UI freezes, buttons unresponsive, typing still works

Potential Root Cause

The list parser enters an infinite while loop:

• Parser sees - as a bullet list marker
• Creates list_item_open/list_item_close tokens each iteration
• state.line never advances (stuck at 2)
• Loop condition while (nextLine < endLine) never exits
• Token array grows indefinitely: 58 → 60 → 62 → ...

Key debugger observations:

nextLine: 2 (never changes)
endLine: 3
state.line: 2 (never advances)
state.lineMax: 1 (incorrect - should be 4)
state.tokens.length: grows by 2 each iteration

Stack trace (constant depth = loop, not recursion):

list.js:305
parser_block.js:80
table.js:228
parser_block.js:80
parser_block.js:124
handlePaste (main.ts:166)

What Works vs What Crashes

Crashes:

 | A |
 |---|
 | - |
 | - |

Works:

| A |
|---|
| - |
| - |

(no leading space)

 | A |
 |---|
 | - |

(only one dash row)

 | A |
 |---|
 | N/A |
 | N/A |

(no standalone dashes)

Note

Vanilla markdown-it (tested v12+) parses the same input correctly. Bug is specific to Confluence's markdown-it integration.

Workarounds

1. Remove leading spaces before pasting
2. Replace - with N/A or —
3. Paste as plain text (Ctrl+Shift+V)

Impact

• Severity: High (browser crash/freeze)
• Data Loss: Unsaved changes after last auto-save are lost

Keywords

Confluence paste markdown table crash, Aw Snap Out of Memory, editor freeze hang, list parser infinite loop, leading space dash cell, OOM browser crash, ProseMirror markdown-it bug

[Trudy Claspill]

Hello @Amr Thabit 

Welcome to the Atlassian community.

As this is a user community, this is not the best venue for trying to report a product bug to Atlassian.

You can check their publicly visible Jira space to see if the bug has already been reported.

https://jira.atlassian.com/secure/Dashboard.jspa

You can report the issue to your local Confluence administrators. They can then report to Atlassian by opening a support case at

https://support.atlassian.com/contact/#/

[Amr Thabit]

Hello Trudy, I posted here for visibility. The bug affects any editor window with no setup. It was a headache trying to narrow down the cause of out of memory error, had to bisect a big block of text, paste and repeat until I found the issue. I don't want to track an issue in 2 place, whoever feels like it can post the issue there, not like I can post an issue there anyway, is this bugged too?

[Trudy Claspill]

No, that is not a bug. Customers are not allowed to add new Bugs directly to Atlassian's tracking system. I only recommended that you look there to see if it was already documented, not that you create a new Bug there.

That is why I suggested that you report it to your Confluence Administrators who can open a support case to escalate it to Atlassian technical support. That team can then open a bug making sure the required information is provided.

[Amr Thabit]

Ah, sorry I didn't understand the ticketing system, though that page should probably display "You're not allowed to post in here". Thanks for the help Trudy. You think someone will notice this bug report in here? I really don't want to reach out to support for this issue.

[Trudy Claspill]

You cannot count on Atlassian team member seeing your post and independently filing a bug report. If you want to ensure that Atlassian acknowledges the issue, going through a support ticket is the path to follow.