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Dir 632 FirmwareOperating system · Dlink

CVE-2025-6121

CRITICAL · 9.8 CVSS v3.1 Published 2025-06-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability, which was classified as critical, has been found in D-Link DIR-632 FW103B08. Affected by this issue is the function get_pure_content of the component HTTP POST Request Handler. The manipulation of the argument Content-Length leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.

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 confidence

A stack-based buffer overflow exists in the get_pure_content function of the D-Link DIR-632 firmware's HTTP POST request handler. By manipulating the Content-Length HTTP header argument, an attacker can overflow a stack buffer, potentially allowing remote code execution. The exploit is publicly available and the affected firmware version is end-of-life.

MitigationSince D-Link DIR-632 is end-of-life with no vendor patch available, immediate mitigation requires network isolation (segmentation), restricting HTTP access to the device, or ideally replacing the device with a supported model. No firmware update will be released by the vendor.

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
Dir 632 FirmwareOperating system
Affected:= 103b08

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify D-Link DIR-632 model
    Check the device model via its web interface status page, device label, or SNMP/sysinfo query. The vulnerability applies only to the DIR-632 hardware model.
    Affected if Device is not a D-Link DIR-632
  2. Check firmware version 103b08
    Access the device's web interface (typically at 192.168.0.1) and navigate to the Status or Firmware Upgrade page to view the installed firmware version. Alternatively, check via command line if telnet/ssh is enabled.
    Affected if Firmware version is exactly 103b08
  3. Verify HTTP service is running
    Attempt an HTTP request to the device's IP address on port 80 (or 443 if HTTPS is enabled). The vulnerability exists in the HTTP POST request handler.
    Affected if HTTP service is not responding or not enabled

A D-Link DIR-632 device running firmware version 103b08 with its HTTP service accessible is affected by CVE-2025-6121.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Since D-Link DIR-632 is end-of-life with no vendor patch available, immediate mitigation requires network isolation (segmentation), restricting HTTP access to the device, or ideally replacing the device with a supported model. No firmware update will be released by the vendor.

Recommended fix High confidence
  1. 1. Since D-Link DIR-632 firmware 103B08 is end-of-life and no longer supported by D-Link, there is no official firmware patch available for this vulnerability.
  2. 2. Replace the D-Link DIR-632 router with a currently supported model from D-Link or another vendor that receives active security updates.
  3. 3. If immediate replacement is not possible, implement network-level mitigations: disable remote management (WAN access) for the router's web interface, place the router behind a properly configured firewall, and restrict access to the LAN-only management interface.
  4. 4. Monitor for any indicators of compromise, as a public exploit exists for this vulnerability.
Caveat The affected product is end-of-life with no available firmware updates; router replacement is required rather than upgrade.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dir 632 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-6121 in production — separate from our analysis above.

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