CVE-2026-15511
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability was determined in Comfast CF-WR631AX V3 up to 2.7.0.8. Affected by this vulnerability is the function system_wl_upload_pic_file of the file /usr/bin/webmgnt of the component FastCGI Backend. This manipulation of the argument filename causes os command injection. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceOS command injection vulnerability in Comfast CF-WR631AX V3 routers (firmware up to 2.7.0.8) allows remote attackers to execute arbitrary commands via manipulation of the filename parameter in the system_wl_upload_pic_file function within the FastCGI backend (/usr/bin/webmgnt). The vulnerability is remotely exploitable without authentication given the CVSS 9.8 critical severity.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify router modelAccess the router's web administration interface and navigate to the status or system information page to confirm the model is Comfast CF-WR631AX V3. Alternatively, check the device label or packaging.Affected if The device is not a Comfast CF-WR631AX V3 router.
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Check firmware versionLog into the router's web interface and locate the firmware version in the status, system, or firmware upgrade section. Compare the displayed version to 2.7.0.8.Affected if The firmware version is 2.7.0.8 or lower.
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Verify web management service is runningAttempt to access the router's web interface on ports 80 or 443 from a browser. Confirm the /usr/bin/webmgnt FastCGI backend is present by accessing the device via SSH or serial console and running: ls -la /usr/bin/webmgntAffected if The web management interface responds and the webmgnt binary exists on the device.
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Check network exposure of web interfaceFrom an external network (or use an online port scanner against your public IP), test if ports 80 and 443 are open and accessible from untrusted networks. Document whether the router is directly exposed to the internet.Affected if Ports 80 or 443 are accessible from untrusted/external networks without firewall filtering.
You are affected if you own a Comfast CF-WR631AX V3 router running firmware version 2.7.0.8 or lower AND the web management interface (ports 80/443) is exposed to untrusted networks.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataSince the vendor did not respond to disclosure, apply compensating controls: disable remote web management and access the administration interface only from trusted local networks, or deploy network segmentation/firewall rules to block external access to the router's web interface on ports 80/443.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-15511 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-15511 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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