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Not in CISA KEV
HIGH severity

CVE-2026-100720 — Froxlor

HIGH

CVE-2026-100720 is a high-severity (CVSS 8.7) Cross-site Scripting (XSS) vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

Froxlor 2.0.0 through 2.3.10 is vulnerable to stored cross-site scripting. When a customer (the lowest-privileged authenticated role) uploads an SSL certificate for one of their own…

Published
Sep 26, 2026
Updated
Sep 26, 2026
Affected
—
Patched
—
Exploits
None indexed
Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Description

Froxlor 2.0.0 through 2.3.10 is vulnerable to stored cross-site scripting. When a customer (the lowest-privileged authenticated role) uploads an SSL certificate for one of their own domains, the Certificates API add()/update() methods parse it with openssl_x509_parse() and store the issuer organization (issuer['O']) value verbatim without sanitization. Froxlor's table-listing renderer then emits scalar cells through Twig's raw filter, disabling HTML auto-escaping, so when an administrator or reseller opens Domains > SSL certificates the attacker-supplied issuer value executes as script in the privileged user's session. This crosses a privilege boundary from customer to admin and can result in full administrator account takeover; because a Froxlor admin controls webserver, DNS, and PHP configuration applied by a cron job running as root, the issue can be further escalated to command execution as root on the managed server. The issue is fixed in Froxlor 2.3.12.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`). Because exploitation targets the running service rather than your application code, O3 also flags the exploit behaviour from runtime telemetry and egress traffic.

  2. Remediation status

    No fixed release is recorded for CVE-2026-100720 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page. O3's runtime protection blocks the cross-site scripting (xss) flaw at execution, which holds the line on hosts you cannot patch immediately.

  4. How O3 protects you

    O3 detects and blocks CVE-2026-100720 exploitation at runtime with eBPF exploit-chain detection, plus L7 egress monitoring that catches a post-exploitation callback and cuts the attacker's outbound channel.

Tailored to CVE-2026-100720. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Froxlor 2.0.0 through 2.3.10 is vulnerable to stored cross-site scripting. When a customer (the lowest-privileged authenticated role) uploads an SSL certificate for one of their own domains, the Certificates API add()/update() methods parse it with openssl_x509_parse() and store the issuer organization (issuer['O']) value verbatim without sanitization. Froxlor's table-listing renderer then emits scalar cells through Twig's `raw` filter, disabling HTML auto-escaping, so when an administrator or reseller opens Domains > SSL certificates the attacker-supplied issuer value executes as script in th
O3 Security · Impact-Aware SCA

Is CVE-2026-100720 in your dependencies?

O3 Security finds CVE-2026-100720 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-100720: Froxlor XSS (High 8.7) | O3 Security