{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "pocketmine/pocketmine-mp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.20.0"
            },
            {
              "fixed": "4.22.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "pocketmine/pocketmine-mp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": true,
    "github_reviewed_at": "2023-07-14T21:50:42Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nA player sending a packet can cause the server to crash by providing incorrect sign data in NBT in `BlockActorDataPacket`.\n\n### Details\nThis vulnerability was discovered using the `BlockActorDataPacket`, but other packets may also be affected. The player would seem to just need to send an NBT with an incorrect type to throw this error.\n\n```\n[Server thread/CRITICAL]: pocketmine\\nbt\\UnexpectedTagTypeException: \"Expected a tag of type pocketmine\\nbt\\tag\\CompoundTag, got pocketmine\\nbt\\tag\\ByteTag\" (EXCEPTION) in \"pmsrc/vendor/pocketmine/nbt/src/tag/CompoundTag\" at line 107\n--- Stack trace ---\n  #0 pmsrc/src/network/mcpe/handler/InGamePacketHandler(751): pocketmine\\nbt\\tag\\CompoundTag-\u003egetCompoundTag(string[9] FrontText)\n  #1 pmsrc/vendor/pocketmine/bedrock-protocol/src/BlockActorDataPacket(50): pocketmine\\network\\mcpe\\handler\\InGamePacketHandler-\u003ehandleBlockActorData(object pocketmine\\network\\mcpe\\protocol\\BlockActorDataPacket#220241)\n  #2 pmsrc/src/network/mcpe/NetworkSession(433): pocketmine\\network\\mcpe\\protocol\\BlockActorDataPacket-\u003ehandle(object pocketmine\\network\\mcpe\\handler\\InGamePacketHandler#190572)\n```\n\n### PoC\nUse a bot or proxy to send a packet when editing a sign. This packet should contain an NBT with incorrect types but correct architecture.\n\n### Impact\nThis makes it possible to shutdown a server for someone who knows how to operate it. As this was discovered in 4.22.1, everyone with at least this version is affected.\n\n### Patches\nThis bug was fixed by 0c250a2ef09627b48aa52302f6cc7e1f2afb70ea in the 4.22.3 and 5.2.1 releases.\n\n### Workarounds\nA plugin may be able to handle `DataPacketReceiveEvent` for `BlockActorDataPacket`, and verify that the `FrontText` tag is a `TAG_Compound`.",
  "id": "GHSA-7wrv-6h42-w54f",
  "modified": "2025-12-26T17:28:18Z",
  "published": "2023-07-14T21:50:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-7wrv-6h42-w54f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pmmp/PocketMine-MP/commit/0c250a2ef09627b48aa52302f6cc7e1f2afb70ea"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pmmp/PocketMine-MP"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PocketMine-MP vulnerable to server crash using badly formatted sign NBT in BlockActorDataPacket"
}