CVE-2026-90937 froxlor CVE debrief

Who should care

Defenders responsible for froxlor installations, particularly those with multi-tenant or shared hosting environments, should assess exposure and prioritize patching or mitigation to prevent potential web server configuration corruption or denial of service. Defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-90937 is a critical vulnerability in froxlor versions before 2.2.5, allowing authenticated customers to inject arbitrary nginx or Apache configuration directives via subdomain redirect URLs. Defenders responsible for froxlor installations should assess exposure and prioritize patching or mitigation to prevent potential web server configuration corruption or denial of service.

• Potential web server configuration corruption or denial of service
• Possible hijacking of HTTP responses across hosted domains
• Need for verification of affected versions and remediation status

Technical summary

The vulnerability is caused by a lack of validation of newline characters in subdomain redirect URLs, allowing attackers to inject arbitrary configuration directives. This can lead to web server configuration corruption, denial of service, or hijacking of HTTP responses across hosted domains. The vulnerability affects froxlor versions before 2.2.5 and can be mitigated by patching to version 2.2.5 or later. Defenders should prioritize patching or mitigating this vulnerability to prevent potential web server configuration corruption or denial of service.

Defensive priority

Defenders should prioritize patching or mitigating this vulnerability to prevent potential web server configuration corruption or denial of service.

Recommended defensive actions

• Patch froxlor to version 2.2.5 or later
• Restrict access to subdomain redirect URL configuration
• Monitor web server configuration and logs for suspicious activity
• 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 vulnerability is caused by a lack of validation of newline characters in subdomain redirect URLs, allowing attackers to inject arbitrary configuration directives. The CVE record was published on 2026-09-14T13:19:32.277Z and has not been modified since then. The official CVE Program record and NIST NVD detail page provide additional information on the vulnerability.

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.