CVE-2026-51600
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 · uneditedTenda CP3 V3.0 firmware V31.1.9.91 does not validate the Content-Length header field in RTSP requests (including DESCRIBE, SETUP, and PLAY methods). When a request carrying a Content-Length header is received without a corresponding message body, the RTSP parser enters a persistent body-awaiting state, causing the affected TCP connection to become permanently non-functional. The device does not actively close the connection, resulting in a TCP resource leak. This issue can be exploited by an unauthenticated remote attacker to cause a denial-of-service condition.
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 confidenceTenda CP3 V3.0 firmware V31.1.9.91 fails to validate the Content-Length header in RTSP requests (DESCRIBE, SETUP, PLAY methods). When a Content-Length header is present without an actual message body, the RTSP parser enters a persistent body-awaiting state, causing the TCP connection to become permanently non-functional without the device actively closing it, leading to TCP resource exhaustion.
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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.
-
Identify the device modelLog into the Tenda router admin panel or check the device label to confirm the model is CP3 V3.0Affected if The device is not a Tenda CP3 V3.0 unit
-
Check the installed firmware versionAccess the router web interface (usually at 192.168.0.1), navigate to System Settings or Firmware Upgrade section, and record the firmware version displayedAffected if The firmware version is V31.1.9.91 or another version in the V31.1.9.x family (compare your version to the affected range)
-
Verify RTSP service is enabledCheck the router settings for RTSP (Real Time Streaming Protocol) configuration, typically found under IP Camera, NAT, or Port Forwarding settings; confirm RTSP service is turned onAffected if RTSP service is enabled on the device
-
Confirm RTSP port is listeningFrom a computer on the same network, run 'telnet <router_ip> 554' or 'nc -zv <router_ip> 554' to test if port 554 is open and respondingAffected if Port 554 (RTSP) is open and accepting connections
-
Assess network exposure of RTSP portCheck router firewall/VLAN settings to determine if port 554 is accessible from external networks (WAN) or untrusted VLANs; document whether the RTSP port is exposed to the internetAffected if RTSP port 554 is accessible from untrusted networks or the WAN interface
You are affected if you have a Tenda CP3 V3.0 device running firmware V31.1.9.91 (or similar affected version) with RTSP service enabled and port 554 accessible from networks where untrusted parties could send malicious RTSP requests.
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 vendor firmware patch when available; until then, restrict network access to RTSP ports (typically 554) via firewall or VLAN segmentation to prevent unauthenticated remote exploitation.
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,152.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-51600 — 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-2026-51600 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data