Router crash via unbounded URL decoding
Published Nov 10, 2025 · Updated Nov 10, 2025
Stack overflow in TOTOLink A7000R firmware 9.1.0u.6115_B20201022 allows remote attackers to crash the router via a crafted POST request. The sub_421CF0 handler passes an attacker-controlled ssid value to urldecode, which writes decoded bytes into a fixed 128-byte stack buffer without enforcing an input-length bound. No authentication or user interaction is required; setting addEffect to 0 reaches the vulnerable branch, and an oversized ssid persistently interrupts routing service.
Summary
What happened
Stack overflow in TOTOLink A7000R firmware 9.1.0u.6115_B20201022 allows remote attackers to crash the router via a crafted POST request. The sub_421CF0 handler passes an attacker-controlled ssid value to urldecode, which writes decoded bytes into a fixed 128-byte stack buffer without enforcing an input-length bound. No authentication or user interaction is required; setting addEffect to 0 reaches the vulnerable branch, and an oversized ssid persistently interrupts routing service.
The record
- CVE
- CVE-2025-63154
- Published
- Nov 10, 2025
- Updated
- Nov 10, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-121, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 10, 2025CVE publishedPublication date reported by the CVE source.
- Nov 10, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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.
Public exploit references
- VulnbyCola A7000R 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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