PocketMine-MP server crash due to incorrect EC curve used for LoginPacket identityPublicKey

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact The server uses ECDH to calculate a shared secret for the symmetric encryption key used to encrypt network packets after logging in. ECDH requires that the keys used must both belong to the same elliptic curve. In Minecraft: Bedrock Edition, the curve used is secp384r1. Using any other curve (for example secp256r1) to sign the LoginPacket JWTs would lead to successfully verifying the login chain, but would later crash due to an uncaught exception during ECDH key derivation due to the client-provided key belonging to a different curve than the server's key. It's also theoretically possible that a non-EC key could be used (e.g. RSA or DH), which would also pass login verification as long as SHA384 hashing algorithm was used for the JWT signatures, and also lead to a crash. Patches The problem was fixed in 4.23.1 and 5.3.1 in the following commit: 4e646d19a4a1e0d082bd4d1f5a58ae0182a268d9 While 4.x would not have crashed when this was encountered, the faulty validation code has…

Published by the source

14 Sep 2023, 17:10 UTC

Last modified by the source

14 Sep 2023, 17:10 UTC

Source last checked

26 Oct 2026, 14:09 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-79rc-jjh6-rc89

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# Patch Next advisory brief: GHSA-79rc-jjh6-rc89

Advisory: PocketMine-MP server crash due to incorrect EC curve used for LoginPacket identityPublicKey
IDs: GHSA-79rc-jjh6-rc89
Record: https://patchnext.com/advisories/ghsa-79rc-jjh6-rc89 (revision 1, source checked 26 Oct 2026, 14:09 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pocketmine/pocketmine-mp 5.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist pocketmine/pocketmine-mp: affected >= 5.2.0, < 5.3.1; fixed in 5.3.1

## Suggested inspection (read-only)
- Packagist pocketmine/pocketmine-mp: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pocketmine/pocketmine-mp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-79rc-jjh6-rc89 (GitHub-reviewed advisory GHSA-79rc-jjh6-rc89 lists affected ranges: Packagist pocketmine/pocketmine-mp >=5.2.0 <5.3.1)

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