Authenticated service interruption via unchecked DDNS provider length
Published Oct 27, 2025 · Updated Oct 27, 2025
Stack overflow in TOTOLINK A3300R 17.0.0cu.557_B20221024 allows remote authenticated users to interrupt router service via DDNS requests. The setDdnsCfg handler stores an overlong provider value through Uci_Set_Str without a length check, and getDdnsCfg later retrieves it into a stack buffer without bounds enforcement. A valid session cookie is required, and the published proof of concept uses separate storage and retrieval requests to trigger the overflow.
Summary
What happened
Stack overflow in TOTOLINK A3300R 17.0.0cu.557_B20221024 allows remote authenticated users to interrupt router service via DDNS requests. The setDdnsCfg handler stores an overlong provider value through Uci_Set_Str without a length check, and getDdnsCfg later retrieves it into a stack buffer without bounds enforcement. A valid session cookie is required, and the published proof of concept uses separate storage and retrieval requests to trigger the overflow.
The record
- CVE
- CVE-2025-12239
- Published
- Oct 27, 2025
- Updated
- Oct 27, 2025
- Vendor
- TOTOLINK
- Product
- A3300R
- Classifications
- CWE-120, CWE-119, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 27, 2025CVE publishedPublication date reported by the CVE source.
- Oct 27, 2025Record 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=17.0.0cu.557_B20221024
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
- A3300R setDdnsCfg stack-overflow proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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