Authenticated stack overflow via unchecked Comment concatenation
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 process memory. The firewall.so setMacFilterRules function appends the request-controlled Comment value with strcat without checking the destination stack buffer's capacity. The published proof of concept requires a valid SESSION_ID cookie and demonstrates the trigger, but it does not document whether the process crashes or attacker-controlled code executes.
Summary
What happened
Stack-based buffer overflow in TOTOLINK A800R 4.1.2cu.5137_B20200730 allows remote authenticated users to corrupt process memory. The firewall.so setMacFilterRules function appends the request-controlled Comment value with strcat without checking the destination stack buffer's capacity. The published proof of concept requires a valid SESSION_ID cookie and demonstrates the trigger, but it does not document whether the process crashes or attacker-controlled code executes.
The record
- CVE
- CVE-2026-19813
- Published
- Aug 14, 2026
- Updated
- Aug 14, 2026
- Vendor
- TOTOLINK
- Product
- A800R
- Classifications
- CWE-121, CWE-119
- 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
- setMacFilterRules stack-overflow 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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