{"id":"GHSA-5jfw-35xp-5m42","aliases":[],"status":"published","title":"Buffer length underflow in LoginPacket causing unchecked exceptions to be thrown","description":"### Impact\n`LoginPacket` uses `BinaryStream-\u003egetLInt()` to read the lengths of JSON payloads it wants to decode. Unfortunately, `BinaryStream-\u003egetLInt()` returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causing `BinaryStream-\u003eget()` to throw an exception.\n\nIn the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited.\n\n### Patches\ne3fce7632b94e83fd6a518a87dcaf6a11681c4ac\n\n### Workarounds\nThis can be worked around by registering a custom `LoginPacket` implementation into `PacketPool` which overrides [this code](https://github.com/pmmp/BedrockProtocol/blob/47532c95ea37d5f0365b23f734d70d943ff95295/src/LoginPacket.php#L54) to patch it.\n\n### For more information\n* Email us at [team@pmmp.io](mailto:team@pmmp.io)","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","from":"ghsa"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-124"],"published":"2022-04-05T17:53:22Z","modified":"2024-12-05T05:39:20Z","fixes":[{"ecosystem":"Packagist","package":"pocketmine/bedrock-protocol","fixed_in":["8.0.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"pocketmine/bedrock-protocol","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.2"}]}]},{"source":"osv","ecosystem":"Packagist","package":"pocketmine/bedrock-protocol","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.2"}]}],"versions":["1.0.0+bedrock-1.17.10","1.1.0+bedrock-1.17.10","2.0.0+bedrock-1.17.30","3.0.0+bedrock-1.17.40","3.0.1+bedrock-1.17.40","3.0.2+bedrock-1.17.40","4.0.0+bedrock-1.17.40","4.0.1+bedrock-1.17.40","5.0.0+bedrock-1.17.40","5.1.0+bedrock-1.17.40","5.1.1+bedrock-1.17.40","5.1.2+bedrock-1.17.40","5.1.3+bedrock-1.17.40","6.0.0+bedrock-1.17.40","7.0.0+bedrock-1.18.0","7.1.0+bedrock-1.18.0","7.2.0+bedrock-1.18.0","7.3.0+bedrock-1.18.0","7.3.1+bedrock-1.18.0","8.0.0+bedrock-1.18.10","8.0.1+bedrock-1.18.10","8.0.2+bedrock-1.18.10"]}],"references":[{"url":"https://github.com/pmmp/BedrockProtocol/security/advisories/GHSA-5jfw-35xp-5m42","tags":["web"]},{"url":"https://github.com/pmmp/BedrockProtocol/commit/e3fce7632b94e83fd6a518a87dcaf6a11681c4ac","tags":["web"]},{"url":"https://github.com/advisories/GHSA-5jfw-35xp-5m42"},{"url":"https://github.com/pmmp/BedrockProtocol","tags":["package"]}],"sources":{"ghsa":[{"id":"GHSA-5jfw-35xp-5m42","title":"Buffer length underflow in LoginPacket causing unchecked exceptions to be thrown","description":"### Impact\n`LoginPacket` uses `BinaryStream-\u003egetLInt()` to read the lengths of JSON payloads it wants to decode. Unfortunately, `BinaryStream-\u003egetLInt()` returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causing `BinaryStream-\u003eget()` to throw an exception.\n\nIn the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited.\n\n### Patches\ne3fce7632b94e83fd6a518a87dcaf6a11681c4ac\n\n### Workarounds\nThis can be worked around by registering a custom `LoginPacket` implementation into `PacketPool` which overrides [this code](https://github.com/pmmp/BedrockProtocol/blob/47532c95ea37d5f0365b23f734d70d943ff95295/src/LoginPacket.php#L54) to patch it.\n\n### For more information\n* Email us at [team@pmmp.io](mailto:team@pmmp.io)","status":"published","published":"2022-04-05T17:53:22Z","modified":"2023-01-11T05:06:31Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-124"],"updated_at":"2026-11-02T14:36:13.23016Z"}],"osv":[{"id":"GHSA-5jfw-35xp-5m42","title":"Buffer length underflow in LoginPacket causing unchecked exceptions to be thrown","description":"### Impact\n`LoginPacket` uses `BinaryStream-\u003egetLInt()` to read the lengths of JSON payloads it wants to decode. Unfortunately, `BinaryStream-\u003egetLInt()` returns a signed integer, meaning that a malicious client can craft a packet with a large uint32 value for payload buffer size (which would be interpreted as a negative signed int32), causing `BinaryStream-\u003eget()` to throw an exception.\n\nIn the context of PocketMine-MP, this leads to a server crash when the vulnerability is exploited.\n\n### Patches\ne3fce7632b94e83fd6a518a87dcaf6a11681c4ac\n\n### Workarounds\nThis can be worked around by registering a custom `LoginPacket` implementation into `PacketPool` which overrides [this code](https://github.com/pmmp/BedrockProtocol/blob/47532c95ea37d5f0365b23f734d70d943ff95295/src/LoginPacket.php#L54) to patch it.\n\n### For more information\n* Email us at [team@pmmp.io](mailto:team@pmmp.io)","status":"published","published":"2022-04-05T17:53:22Z","modified":"2024-12-05T05:39:20.852353Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-124"],"updated_at":"2026-11-02T15:46:38.553953Z"}]}}