# CVE-2026-15511: Comfast CF-WR631AX V3 command injection in FastCGI Backend

Source: https://junglewise.ai/threats/cve-2026-15511-comfast-cf-wr631ax-v3-command-injection-in-fastcgi-backend  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-12. Updated: 2026-07-12  
License: CC BY 4.0 with a link back

CVE-2026-15511 · Severity: critical · CVSS 9.8 · Published 2026-07-12

A vulnerability exists in the Comfast CF-WR631AX V3 wireless router, a device used to provide high-speed Wi-Fi connectivity. An attacker can remotely take full control of the router by sending a specially crafted file upload request. This could lead to the theft of sensitive data, interception of network traffic, or a complete shutdown of the internet service.

Vendors: [Comfast](https://junglewise.ai/threats/vendors/comfast).

## Quick answers

**Is CVE-2026-15511 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15511 being exploited in the wild.

**How severe is CVE-2026-15511?** Critical severity, with a CVSS score of 9.8, published 12 July 2026.

**Which products and versions are affected?** Comfast CF-WR631AX V3 2.7.0.0 to 2.7.0.8.

**Is there a fix for CVE-2026-15511?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15511 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-15511?** Check whether you run Comfast CF-WR631AX V3 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An OS command injection vulnerability exists in the Comfast CF-WR631AX V3 router (firmware versions up to 2.7.0.8). The flaw is located within the 'system_wl_upload_pic_file' function of the '/usr/bin/webmgnt' binary, which serves as the FastCGI Backend. By manipulating the 'filename' argument during a WiFi portal image upload, a remote attacker can execute arbitrary system commands without authentication. This occurs due to improper neutralization of special elements used in an OS command (CWE-78). As of the advisory date, the vendor has not responded to disclosure attempts, and no patch is currently available.

## Affected products

- Comfast CF-WR631AX V3 2.7.0.0 to 2.7.0.8

## Timeline

- 2026-07-12: disclosed: Public disclosure of the vulnerability and exploit details.
- 2026-07-12: advisory

## References

- [https://github.com/luminarydawn/cve/tree/main/Command%20Injection%20in%20Comfast%20CF-WR631AX%20V3%20%E2%80%94%20WiFi%20Portal%20Image%20Upload%20(CWE-78)](https://github.com/luminarydawn/cve/tree/main/Command%20Injection%20in%20Comfast%20CF-WR631AX%20V3%20%E2%80%94%20WiFi%20Portal%20Image%20Upload%20(CWE-78))
- [https://vuldb.com/cve/CVE-2026-15511](https://vuldb.com/cve/CVE-2026-15511)
- [https://vuldb.com/submit/846719](https://vuldb.com/submit/846719)
- [https://vuldb.com/vuln/377840](https://vuldb.com/vuln/377840)
- [https://vuldb.com/vuln/377840/cti](https://vuldb.com/vuln/377840/cti)

## Related threats

- [Comfast CF-WR631AX V3 OS command injection in ping_config API](https://junglewise.ai/threats/cve-2026-12814-comfast-cf-wr631ax-v3-os-command-injection-in-ping-config-api)