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D-Link routers HNAP service contains stack-based buffer overflow

Vulnerability Note VU#677427

Original Release Date: 2016-11-07 | Last Revised: 2017-03-08


D-Link DIR routers contain a stack-based buffer overflow in the HNAP Login action.


CWE-121: Stack-based Buffer Overflow - CVE-2016-6563

Processing malformed SOAP messages when performing the HNAP Login action causes a buffer overflow in the stack. The vulnerable XML fields within the SOAP body are: Action, Username, LoginPassword, and Captcha.

CVE-2016-6563 appears to affect:

    • DIR-823
    • DIR-822
    • DIR-818L(W)
    • DIR-895L
    • DIR-890L
    • DIR-885L
    • DIR-880L
    • DIR-868L
    • DIR-850L


A remote, unauthenticated attacker may be able to execute arbitrary code with root privileges.


Apply an update
D-Link has released firmware updates to address the vulnerabilities in affected routers. Please see their announcement.
If you are unable to update your device, please see the following workarounds:

Restrict Access

As a general good security practice, only allow connections from trusted hosts and networks. Additionally, you may wish to disable remote administration of the router.

Vendor Information

Affected   Unknown   Unaffected

D-Link Systems, Inc.

Notified:  September 12, 2016 Updated:  October 27, 2016



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

CVSS Metrics

Group Score Vector
Base 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C
Temporal 8.0 E:POC/RL:W/RC:ND
Environmental 6 CDP:N/TD:M/CR:ND/IR:ND/AR:ND



Thanks to Pedro Ribeiro ( of Agile Information Security for reporting this vulnerability.

This document was written by Trent Novelly.

Other Information

CVE IDs: CVE-2016-6563
Date Public: 2016-11-07
Date First Published: 2016-11-07
Date Last Updated: 2017-03-08 15:16 UTC
Document Revision: 22

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