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  1. Minecraft: Java Edition
  2. MC-190478

Commands that exceed chat length limit can still be executed in servers that have disabled command blocks

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • None
    • 1.15.2, 1.16 Release Candidate 1, 1.16, 1.16.1, 20w27a, 20w28a, 20w29a, 20w30a, 1.16.2 Pre-release 1, 1.16.2 Pre-release 2, 1.16.2 Pre-release 3, 1.16.2 Release Candidate 1, 1.16.2 Release Candidate 2, 1.16.2, 1.16.3 Release Candidate 1, 1.16.3, 1.16.4 Pre-release 1, 1.16.4 Pre-release 2, 1.16.4 Release Candidate 1, 1.16.4, 20w45a, 20w46a, 20w48a, 20w49a, 20w51a, 21w03a, 21w05b, 21w06a, 21w07a, 21w08b, 21w10a, 21w11a, 21w13a, 21w14a, 21w39a, 22w14a, 1.19.2, 1.19.4
    • None
    • Confirmed
    • Commands, UI

      The Bug

      Players can access commands longer than the chat character limit using custom signs. This can be used to execute long commands that can't normally be executed without the use of command blocks.

      How to reproduce

      1. Open a Creative world where you have operator permissions (it could be a brand new single player world, it doesn't matter).
      2. Use a command block to give yourself a sign that executes a special command when clicked. To properly reproduce this bug, make sure that the command stored in the sign is one of the Examples included at the bottom of this report.
      3. Save this pre-filled sign in a slot in one of your Saved Hotbars.
      4. Join a server in which you have operator permissions and are in Creative mode.
      5. Load in the Saved Hotbar.
      6. Place the sign(s) down. They should have the same text as was programmed before.
      7. Right click the sign.

      Notice how the command that usually would not be accessible on a server with command blocks disabled could execute properly here.

      Example commands

      Example 1: Give yourself a custom player head (561 characters)

      /give @p minecraft:oak_sign{BlockEntityTag:{Text1:'{"text":"Custom Head!","clickEvent":{"action":"run_command","value":"give @p minecraft:player_head{display:{Name:\\"{\\\\\\"text\\\\\\":\\\\\\"Exhausted Bee\\\\\\"}\\"},SkullOwner:{Id:\\"54087a9e-d70d-4fb4-9fe1-042ae7449847\\",Properties:{textures:[{Value:\\"eyJ0ZXh0dXJlcyI6eyJTS0lOIjp7InVybCI6Imh0dHA6Ly90ZXh0dXJlcy5taW5lY3JhZnQubmV0L3RleHR1cmUvNmNjOTM2Yjk0MTgwODcyNzY3MDA4ZTNjNDI3NTRjN2FjN2FjMzQ4ZDRlMjJlOTI0ODI3MzQ0ZWMyYTY2ZjJiNCJ9fX0=\\"}]}}} 1"},"italic":true}'},display:{Name:'{"text":"Custom Head!"}'}}

      Example 2: Give yourself a sword with powerful enchantments (421 characters)

      /give @p minecraft:oak_sign{BlockEntityTag:{Text1:'{"text":"Custom Sword!","clickEvent":{"action":"run_command","value":"give @s diamond_sword{Enchantments:[{id:sharpness,lvl:32767},{id:unbreaking,lvl:32767},{id:knockback,lvl:10},{id:fire_aspect,lvl:32767},{id:looting,lvl:10},{id:sweeping_edge,lvl:10},{id:mending,lvl:1},{id:bane_of_arthropods,lvl:32767}]} 1"},"italic":true}'},display:{Name:'{"text":"Custom Sword!"}'}}

      Example 3: Spam chat with big bold underlined italicized red text (4050 characters)

      /give @p minecraft:oak_sign{BlockEntityTag:{Text1:'{"text":"Tellraw @a!","clickEvent":{"action":"run_command","value":"tellraw @a {\\"text\\":\\"MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!MOJIRA!MC-190478!\\",\\"bold\\":true,\\"italic\\":true,\\"underlined\\":true,\\"color\\":\\"red\\",\\"clickEvent\\":{\\"action\\":\\"open_url\\",\\"value\\":\\"https://bugs.mojang.com/browse/MC-190478\\"}}"}}'},display:{Name:'{"text":"Tellraw @a"}'}}

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            markderickson [Mod] markderickson
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              Created:
              Updated:
              CHK: