Authenticated stack corruption via unchecked comment copy
Published Aug 14, 2026 · Updated Aug 14, 2026
Stack-based buffer overflow in TOTOLINK A800R 4.1.2cu.5137_B20200730 allows remote authenticated users to corrupt the service stack. The setIpQosRules function in firewall.so copies the request-controlled comment value with strcpy without checking its length, overflowing a stack buffer. A valid management session is required; the public proof of concept supplies a triggering HTTP request but demonstrates neither code execution nor in-the-wild exploitation.
Summary
What happened
Stack-based buffer overflow in TOTOLINK A800R 4.1.2cu.5137_B20200730 allows remote authenticated users to corrupt the service stack. The setIpQosRules function in firewall.so copies the request-controlled comment value with strcpy without checking its length, overflowing a stack buffer. A valid management session is required; the public proof of concept supplies a triggering HTTP request but demonstrates neither code execution nor in-the-wild exploitation.
The record
- CVE
- CVE-2026-19811
- Published
- Aug 14, 2026
- Updated
- Aug 14, 2026
- Vendor
- TOTOLINK
- Product
- A800R
- Classifications
- CWE-119, CWE-121
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 14, 2026CVE publishedPublication date reported by the CVE source.
- Aug 14, 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=4.1.2cu.5137_B20200730
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
- TOTOLINK A800R setIpQosRules HTTP proof of conceptproof of concept · unverified
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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