Authenticated code execution via unchecked upload filename
Published Mar 31, 2026 · Updated Mar 31, 2026
Stack-based overflow in D-Link DNS and DNR firmware through 20260205 allows remote authenticated users to execute arbitrary code. A crafted multipart f_file filename is copied into a stack-local buffer in Webdav_Upload_File without a length check, overwriting the return address. Authenticated access to webdav_mgr.cgi is required; the demonstrated payload persistently crashes services, while return-address control enables code execution.
Summary
What happened
Stack-based overflow in D-Link DNS and DNR firmware through 20260205 allows remote authenticated users to execute arbitrary code. A crafted multipart f_file filename is copied into a stack-local buffer in Webdav_Upload_File without a length check, overwriting the return address. Authenticated access to webdav_mgr.cgi is required; the demonstrated payload persistently crashes services, while return-address control enables code execution.
The record
- CVE
- CVE-2026-5212
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Vendor
- D-Link
- Product
- DNR-322L
- Classifications
- CWE-787, CWE-119, CWE-121, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 31, 2026CVE publishedPublication date reported by the CVE source.
- Mar 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=20260205
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- D-Link webdav_mgr.cgi filename overflow proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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