CVE-2026-107809 0xJacky CVE debrief

Who should care

Defenders responsible for Nginx-UI deployments, especially those with administrator accounts without OTP/Passkey or target endpoints that do not require secure-session proof, should assess exposure and prioritize remediation.

Why it matters

CVE-2026-107809 allows a remote attacker to induce a logged-in administrator's browser to submit authenticated cross-site state-changing requests. Defenders should prioritize verifying exposure of Nginx-UI management APIs and ensure administrators use secure-session proof or OTP/Passkey.

• An attacker can modify Nginx configuration, trigger reloads, or invoke other management operations reachable with the victim's session.
• Defenders need to verify exposure of Nginx-UI management APIs, especially for versions between 2.0.0 and 2.5.0.
• Remediation priority follows from verifying and upgrading to version 2.5.0 or later.
• Further verification is required to determine potential exploitation or specific attacks.

Technical summary

The Nginx-UI AuthRequired token cookie fallback enables CSRF against management APIs in versions between 2.0.0 and 2.5.0. An attacker can induce a logged-in administrator's browser to submit authenticated cross-site state-changing requests. This issue allows a remote attacker to modify Nginx configuration, trigger reloads, or invoke other management operations reachable with the victim's session. Defenders should prioritize verifying exposure of Nginx-UI management APIs, especially for versions between 2.0.0 and 2.5.0, and ensure administrators use secure-session proof or OTP/Passkey.

Defensive priority

Defenders should prioritize verifying exposure of Nginx-UI management APIs, especially for versions between 2.0.0 and 2.5.0, and ensure administrators use secure-session proof or OTP/Passkey.

Recommended defensive actions

• Verify Nginx-UI version and ensure it is 2.5.0 or later
• Restrict access to Nginx-UI management APIs to trusted users and networks
• Implement CSRF protection for Nginx-UI management APIs
• Enforce secure-session proof or OTP/Passkey for administrator accounts
• 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

Evidence notes

Evidence from the CVE Program record and Nginx-UI source references indicates that the issue is fixed in version 2.5.0. However, details about potential exploitation or specific attacks are limited. Defenders should verify exposure of Nginx-UI management APIs, especially for versions between 2.0.0 and 2.5.0, and ensure administrators use secure-session proof or OTP/Passkey. The CVE Program record and source references provide limited information about the vulnerability, and defenders need to take extra steps to verify and remediate.

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.