Authenticated code execution via unchecked f_dir copy
Published Mar 31, 2026 · Updated Mar 31, 2026
Stack overflow in D-Link DNS and DNR appliances version 20260205 allows remote authenticated users to execute arbitrary code. UPnP_AV_Server_Path_Del in /cgi-bin/app_mgr.cgi copies an unchecked f_dir value into a stack-local buffer, overwriting the return address. Exploitation requires an authenticated session; the published request uses an admin cookie and demonstrates a persistent service crash.
Summary
What happened
Stack overflow in D-Link DNS and DNR appliances version 20260205 allows remote authenticated users to execute arbitrary code. UPnP_AV_Server_Path_Del in /cgi-bin/app_mgr.cgi copies an unchecked f_dir value into a stack-local buffer, overwriting the return address. Exploitation requires an authenticated session; the published request uses an admin cookie and demonstrates a persistent service crash.
The record
- CVE
- CVE-2026-5211
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Vendor
- D-Link
- Product
- DNR-322L
- Classifications
- CWE-121, CWE-119, CWE-787, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=20260205
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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 app_mgr.cgi UPnP_AV_Server_Path_Del PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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