CVE-2026-100717
CVE-2026-100717 — froxlor before 2.3.12 CRLF Injection via validateUrl userinfo
froxlor is a server administration panel. In versions 2.3.10 and earlier, Validate::validateUrl rejects carriage return and line feed characters only in the path, query and fragment components returned by parse_url, and never inspects the userinfo (user:pass@) components. This is an incomplete fix for GHSA-c3p2. An authenticated low-privilege customer with subdomain-create rights (no admin or change_serversettings privilege required) can supply a subdomain redirect URL that carries a CR/LF payload in the userinfo portion (e.g. http://user%0areturn 200 "pwned";%[email protected]/). The value passes validation, survives IDNA encoding, and is written verbatim into the generated nginx or Apache vhost configuration, allowing the attacker to break out of the emitted directive and inject arbitrary web-server configuration lines. froxlor regenerates and reloads the web-server configuration as root, so the injected directives take effect server-wide and can hijack responses or read local files. The issue is fixed in version 2.3.12.
Published Updated Sources: NVD, froxlor (CNA), GitHub
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Exploit code
public exploit, none observed
EPSS
Not scored
FIRST has not published a score
CVSS base
9.9
critical · 2 sources
Remediation
The vendor's own words where we have them.
Upgrade froxlor to a fixed release (2.3.12). Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| froxlor | froxlor | 0 to < 2.3.12 | Vulnerable |
| froxlor | froxlor | 2.3.12 | Patched |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
Low
Integrity
High
Scope
Changed
Attack Complexity
Low
Attack Vector
Network
Privileges Req
Low
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 9.9 | CVSS 3.1 | critical | 3.1 | 6 | NVD, froxlor (CNA) |
| 8.5 | CVSS 4.0 | high | — | — | froxlor (CNA) |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H
Weakness & attack patterns
- CWE-93
Inferred from the weakness class — not observed against this CVE.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Repositories
2
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /LF, //user%0areturn, /).
- Prioritize edge telemetry for network-reachable froxlor.
- Monitor for scanner or exploit-pattern traffic after 2 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 9.9 (AV:N)
Sep 26, 2026 · NVD
Initial · CVE published
Sep 26, 2026 · NVD
References
2 on the record
- github.com/froxlor/froxlor/security/advisories/GHSA-gxx3-hwjc-h2gp
Exploit, Third Party Advisory
- www.vulncheck.com/advisories/froxlor-before-2.3.12-crlf-injection-via-validateurl-userinfo
Vendor Advisory
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-100717 is froxlor before 2.3.12 CRLF Injection via validateUrl userinfo, a critical vulnerability affecting froxlor from froxlor. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-100717. Public exploit evidence is: 2 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.9 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.