How severe is CVE-2023-54393?

No CVSS score has been assigned to CVE-2023-54393 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2023-54393?

CVE-2023-54393 affects the following packages: pocketmine/pocketmine-mp (Packagist), pocketmine/pocketmine-mp (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2023-54393?

Update pocketmine/pocketmine-mp to 4.20.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-54393 is resolved across your whole dependency graph.

How do I detect CVE-2023-54393 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pocketmine/pocketmine-mp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-54393 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2023-54393 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-54393 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-54393?

CVE-2023-54393 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 50th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-54393?

CVE-2023-54393 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-54393 published, and has it been updated?

CVE-2023-54393 was published on September 9, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2023-54393 — pocketmine-mp

Fix: pmmp/PocketMine-MP@09668a3

CVE-2023-54393 is a Improper Input Validation vulnerability in pocketmine/pocketmine-mp. A fix is available for pocketmine/pocketmine-mp — see the affected versions and patch details below.

PocketMine-MP before 4.20.5 Denial of Service via LoginPacket

Also known asGHSA-pqp3-8rrw-g8vm

Published

Sep 9, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-54393.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘pocketmine/pocketmine-mp🐘pocketmine/pocketmine-mp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

An attacker could crash PocketMine-MP by sending malformed JSON in LoginPacket.

This happened due to a bug in netresearch/jsonmapper. The library wasn't doing proper checks when mapping JSON arrays and objects onto scalar model properties such as strings.

Patches

The problem was fixed in a fork of JsonMapper in dktapps/JsonMapper@a31902a31f5b6fdb832f57c0e3a3f16a3b41c012. PocketMine-MP releases 4.20.5 and 4.21.1 have been released with the fix.

Workarounds

Users of PocketMine-MP source installations may manually install the patched version of JsonMapper by backporting commit pmmp/PocketMine-MP@09668a37d66c6023685a948b7550c918620e98f2.
A plugin may also be able to workaround this issue by using DataPacketReceiveEvent to attempt detection of suspicious payloads. An ErrorException will be thrown in the crash case, which can be caught by plugins.

References

cweiske/jsonmapper#210

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`pocketmine/pocketmine-mp`	all versions	4.20.5`composer require pocketmine/pocketmine-mp:^4.20.5`
🐘Packagist	`pocketmine/pocketmine-mp`	≥ 4.21.0&&< 4.21.1	4.21.1`composer require pocketmine/pocketmine-mp:^4.21.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pocketmine/pocketmine-mp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pocketmine/pocketmine-mp to 4.20.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-54393 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact An attacker could crash PocketMine-MP by sending malformed JSON in `LoginPacket`. This happened due to a bug in [`netresearch/jsonmapper`](https://github.com/cweiske/JsonMapper). The library wasn't doing proper checks when mapping JSON arrays and objects onto scalar model properties such as strings. ### Patches The problem was fixed in a fork of JsonMapper in dktapps/JsonMapper@a31902a31f5b6fdb832f57c0e3a3f16a3b41c012. PocketMine-MP releases 4.20.5 and 4.21.1 have been released with the fix. ### Workarounds - Users of PocketMine-MP source installations may manually install the pa

O3 Security · Impact-Aware SCA

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