CVE-2020-25757
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 lack of input validation and access controls in Lua CGIs on D-Link DSR VPN routers may result in arbitrary input being passed to system command APIs, resulting in arbitrary command execution with root privileges. This affects DSR-150, DSR-250, DSR-500, and DSR-1000AC with firmware 3.14 and 3.17.
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 confidenceCommand injection vulnerability in Lua CGI scripts on D-Link DSR VPN routers (DSR-150, DSR-250, DSR-500, DSR-1000AC with firmware 3.14/3.17). Lack of input validation and missing access controls allow arbitrary input to be passed to system command APIs, enabling unauthenticated attackers to execute arbitrary commands with root privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 3.17<= 3.17<= 3.17<= 3.17<= 3.17all versions<= 3.17<= 3.17CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/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 D-Link DSR router modelAccess the router web interface, check the device label, or query the device via SNMP/system information to confirm the exact model number (DSR-150, DSR-150N, DSR-250, DSR-250N, DSR-500, DSR-500N, DSR-500AC, or DSR-1000).Affected if Model is any DSR variant listed in the affected products.
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Check installed firmware versionLog into the router web interface (typically at 192.168.0.1 or 10.0.0.1), navigate to Status or System section, and record the firmware version displayed. Alternatively, use SNMP OID .1.3.6.1.2.1.1.1.0 or check via command line if available.Affected if Firmware version is 3.17 or lower, or for DSR-500N any version number.
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Verify if remote management CGI interface is exposedAttempt to access common CGI paths such as /cgi-bin/luci, /cgi-bin/cgi_handler, or test for Lua CGI script endpoints from an external network interface. Check router firewall settings to see if HTTP/HTTPS management ports (80/443) are listening on WAN interfaces.Affected if Remote management interface is accessible from untrusted networks (WAN-facing).
Device is affected if it is a D-Link DSR model (150/150N/250/250N/500/500N/500AC/1000) with firmware at or below version 3.17 (or any DSR-500N version) and the router's CGI-based management interface is exposed to the network being tested.
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 dataApply available firmware updates from D-Link. If patches are unavailable, disable remote management interfaces, restrict network access to trusted IPs only, and consider network segmentation to limit exposure.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-25757 — 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-2020-25757 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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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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