CVE-2026-100390 tobychui CVE debrief

Who should care

Defenders responsible for Zoraxy instances, particularly those exposed to IPv6 connections or utilizing IP-based access controls, should assess their exposure and verify the effectiveness of their current security measures.

Why it matters

CVE-2026-100390 allows unauthenticated attackers to bypass IP-based access controls in Zoraxy versions 3.2.3 through 3.3.4 by spoofing their source IP address using IPv6 connections. Defenders should verify exposure of Zoraxy instances to IPv6 and assess the effectiveness of current IP-based access controls.

• Potential bypass of IP-based access controls
• Possible spoofing of source IP addresses
• Need for verification of Zoraxy instance exposure to IPv6
• Potential impact on authentication and authorization mechanisms

Technical summary

Zoraxy versions 3.2.3 through 3.3.4 fail to properly parse IPv6 addresses in the RemoteAddr field when setting forwarded headers, allowing unauthenticated attackers to supply arbitrary X-Forwarded-For values to spoof their source IP and bypass authorization provider IP-based access controls. This vulnerability enables attackers to potentially bypass IP-based access controls and possibly spoof source IP addresses, impacting authentication and authorization mechanisms. Defenders should prioritize verifying exposure of Zoraxy instances to IPv6 connections and assessing the effectiveness of current IP-based access controls.

Defensive priority

Defenders should prioritize verifying exposure of Zoraxy instances to IPv6 connections and assessing the effectiveness of current IP-based access controls.

Recommended defensive actions

• Verify exposure of Zoraxy instances to IPv6 connections
• Assess the effectiveness of current IP-based access controls
• Update Zoraxy to a version outside of 3.2.3 through 3.3.4 if available
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in Zoraxy versions 3.2.3 through 3.3.4, which fails to properly parse IPv6 addresses in the RemoteAddr field when setting forwarded headers.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.