CVE-2025-12611
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 identified in Tenda AC21 16.03.08.16. This vulnerability affects the function formSetPPTPServer of the file /goform/SetPptpServerCfg. The manipulation of the argument startIp leads to buffer overflow. Remote exploitation of the attack is possible. The exploit is publicly available and might be used.
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 confidenceA buffer overflow vulnerability exists in Tenda AC21 firmware 16.03.08.16 within the formSetPPTPServer function of /goform/SetPptpServerCfg. The startIp parameter passed to this PPTP server configuration endpoint is not properly bounds-checked before being copied into a fixed-size buffer, allowing remote attackers to overflow the buffer and potentially execute arbitrary code or cause denial of service.
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= 16.03.08.16CVSS 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.
-
Identify device modelCheck the device model label on the router or access the admin interface to confirm it is a Tenda AC21 deviceAffected if Device is not a Tenda AC21 model
-
Check firmware versionAccess the router admin interface (typically at 192.168.0.1) and navigate to System Settings or Firmware Upgrade to view the installed firmware version, or use telnet/SSH to check /proc/version or nvram settings if availableAffected if Firmware version is 16.03.08.16 exactly
-
Determine if PPTP server feature existsAccess the router admin interface and look for PPTP server, VPN server, or similar configuration sections under Advanced Settings or Network SettingsAffected if PTP server configuration interface is present and accessible
-
Check PPTP server statusIn the router admin interface, check if the PPTP server feature is enabled or configuredAffected if PTP server is enabled or has been configured on the device
User is affected if they have a Tenda AC21 router running firmware version 16.03.08.16 with the PPTP server feature accessible or enabled on the network.
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 update when available; if no update exists, disable the PPTP server feature on the device or place the device behind a firewall with restrictive access controls to limit exposure to unauthenticated attackers.
- 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-2025-12611 — 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-2025-12611 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