CVE-2025-34036
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 · uneditedAn OS command injection vulnerability exists in white-labeled DVRs manufactured by TVT, affecting a custom HTTP service called "Cross Web Server" that listens on TCP ports 81 and 82. The web interface fails to sanitize input in the URI path passed to the language extraction functionality. When the server processes a request to /language/[lang]/index.html, it uses the [lang] input unsafely in a tar extraction command without proper escaping. This allows an unauthenticated remote attacker to inject shell commands and achieve arbitrary command execution as root. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.
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 TVT white-labeled DVRs' Cross Web Server (ports 81/82). The /language/[lang]/index.html endpoint passes the lang parameter unsafely to a tar extraction command without input sanitization, allowing unauthenticated remote attackers to inject shell commands and achieve root-level arbitrary command execution.
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 dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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 the DVR modelAccess the device administrative interface or check the device label/system information to confirm the exact model number (e.g., Tvt Td 2108ts Cl, Tvt Td 2116ts Hc, etc.)Affected if The model matches any of the following: Tvt Td 2108ts Cl, Tvt Td 2108ts Cl A, Tvt Td 2116ts Cl, Tvt Td 2104ts Hc, Tvt Td 2108ts Hc, Tvt Td 2116ts Hc, Tvt Td 2104ts Hp, or Tvt Td 2108ts Hp
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Verify Cross Web Server ports are accessibleScan the device for open ports 81 and 82 using a network scanner (e.g., nmap -p 81,82 [device_ip]) or check firewall rulesAffected if Ports 81 or 82 are open and accessible on the device, indicating the Cross Web Server is running
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Confirm the vulnerable endpoint existsSend an HTTP request to http://[device_ip]:81/language/test/index.html and observe the responseAffected if The endpoint responds (even with an error), confirming the /language/[lang]/index.html path is active
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Check network exposure of ports 81/82Review firewall rules, NAT configurations, or ACLs to determine if ports 81/82 are exposed to untrusted networks or the internetAffected if Ports 81 or 82 are reachable from untrusted networks (such as the internet) without authentication
Your environment is affected if you operate any of the listed TVT DVR models and the Cross Web Server on ports 81/82 is accessible, particularly if 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.
dbcve · scopedImmediately restrict network access to ports 81 and 82 via firewall. Contact TVT for firmware update to patch the command injection. Monitor for indicators of compromise given active exploitation observed by Shadowserver.
- Implement network segmentation to isolate the affected DVR devices on a separate VLAN from critical systems
- Block inbound access to TCP ports 81 and 82 at the network perimeter firewall for all untrusted external networks
- If the devices must be accessible, implement IP whitelisting on the firewall to restrict access to only trusted source IP addresses
- Monitor network traffic for indicators of compromise such as unusual HTTP requests to /language/ paths with shell metacharacters (e.g., |, ;, $, `, &&)
- Consider deploying an Intrusion Detection System (IDS) or Web Application Firewall (WAF) capable of detecting and blocking OS command injection attempts
- If device replacement is feasible, migrate to newer DVR hardware from vendors that provide regular security firmware updates
- Document the vulnerability and current mitigations for compliance and incident response purposes
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-34036 — 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-2025-34036 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
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