Authenticated code execution via unchecked sprintf
Published Mar 29, 2026 · Updated Mar 29, 2026
Stack-based buffer overflow in Tenda F453 1.0.0.3 allows remote authenticated users to execute code via a crafted delno parameter. Within httpd's fromPPTPUserSetting handler, an unchecked sprintf copies the delno-derived s_3 value into the fixed-size stack buffer s__1. The HTTP request requires low-privilege access, and successful exploitation can crash the router or execute code in the httpd process.
Summary
What happened
Stack-based buffer overflow in Tenda F453 1.0.0.3 allows remote authenticated users to execute code via a crafted delno parameter. Within httpd's fromPPTPUserSetting handler, an unchecked sprintf copies the delno-derived s_3 value into the fixed-size stack buffer s__1. The HTTP request requires low-privilege access, and successful exploitation can crash the router or execute code in the httpd process.
The record
- CVE
- CVE-2026-5021
- Published
- Mar 29, 2026
- Updated
- Mar 29, 2026
- Vendor
- Shenzhen Tenda Technology Co., Ltd.
- Product
- F453
- Classifications
- CWE-119, CWE-121, CWE-787, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 29, 2026CVE publishedPublication date reported by the CVE source.
- Mar 29, 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=1.0.0.3
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
- F453 fromPPTPUserSetting delno PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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