Authenticated command execution via unescaped upload filename
Published Feb 23, 2026 · Updated Feb 23, 2026
OS command injection in DrayTek Vigor300B Web Management Interface 1.5.1.0 through 1.5.1.6 allows remote authenticated users to execute commands. The cgiGetFile upload handler applies HTML-only cgiEscape sanitization to an attacker-controlled filename before using it in a shell-based file move, leaving shell metacharacters unescaped. Administrative credentials and network access to /cgi-bin/mainfunction.cgi/uploadlangs are required; injected filename syntax runs commands with the appliance's web-management privileges.
Summary
What happened
OS command injection in DrayTek Vigor300B Web Management Interface 1.5.1.0 through 1.5.1.6 allows remote authenticated users to execute commands. The cgiGetFile upload handler applies HTML-only cgiEscape sanitization to an attacker-controlled filename before using it in a shell-based file move, leaving shell metacharacters unescaped. Administrative credentials and network access to /cgi-bin/mainfunction.cgi/uploadlangs are required; injected filename syntax runs commands with the appliance's web-management privileges.
The record
- CVE
- CVE-2026-3040
- Published
- Feb 23, 2026
- Updated
- Feb 23, 2026
- Vendor
- DrayTek
- Product
- Vigor300B
- Classifications
- CWE-77, CWE-78, T1059.004
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Feb 23, 2026CVE publishedPublication date reported by the CVE source.
- Feb 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.5.1.0
- Affected versionversion=1.5.1.1
- Affected versionversion=1.5.1.2
- Affected versionversion=1.5.1.3
- Affected versionversion=1.5.1.4
- Affected versionversion=1.5.1.5
- Affected versionversion=1.5.1.6
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Vigor300B uploadlangs malicious-filename proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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