Summary
PocketMine-MP server crash due to incorrect EC curve used for LoginPacket identityPublicKey
Workarounds
A plugin could handle LoginPacket and check that all of the identityPublicKeys provided in the JWT bodies actually belong to secp384r1. This can be checked by verifying that openssl_pkey_get_details($key)["ec"]["curve_name"] is set and equal to secp384r1. Beware that this element may not exist if the key is not an EC key at all.
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.
GHSA-79RC-JJH6-RC89 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.3.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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 also been corrected there.
Frequently Asked Questions
- What is GHSA-79RC-JJH6-RC89? GHSA-79RC-JJH6-RC89 is a high-severity security vulnerability in pocketmine/pocketmine-mp (composer), affecting versions >= 5.2.0, < 5.3.1. It is fixed in 5.3.1.
- How severe is GHSA-79RC-JJH6-RC89? GHSA-79RC-JJH6-RC89 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pocketmine/pocketmine-mp are affected by GHSA-79RC-JJH6-RC89? pocketmine/pocketmine-mp (composer) versions >= 5.2.0, < 5.3.1 is affected.
- Is there a fix for GHSA-79RC-JJH6-RC89? Yes. GHSA-79RC-JJH6-RC89 is fixed in 5.3.1. Upgrade to this version or later.
- Is GHSA-79RC-JJH6-RC89 exploitable, and should I be worried? Whether GHSA-79RC-JJH6-RC89 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-79RC-JJH6-RC89 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-79RC-JJH6-RC89? Upgrade
pocketmine/pocketmine-mpto 5.3.1 or later.