Memory disclosure via uninitialized UPnP response buffer
Published Jun 3, 2026 · Updated Jun 3, 2026
Information disclosure in Mercusys AC12G (EU) V1 firmware AC12G(EU)_V1_200909 allows remote attackers to read internal memory via UPnP. The UPnP HTTP server returns 128 bytes from an uninitialized shared response buffer when a port 1900 POST request omits SOAPAction, exposing current headers, prior response fragments, and buffer-management contents. No authentication is required, but remote attackers must reach the router from its local network; each request discloses 128 bytes without changing device state.
Summary
What happened
Information disclosure in Mercusys AC12G (EU) V1 firmware AC12G(EU)_V1_200909 allows remote attackers to read internal memory via UPnP. The UPnP HTTP server returns 128 bytes from an uninitialized shared response buffer when a port 1900 POST request omits SOAPAction, exposing current headers, prior response fragments, and buffer-management contents. No authentication is required, but remote attackers must reach the router from its local network; each request discloses 128 bytes without changing device state.
The record
- CVE
- CVE-2026-36611
- Published
- Jun 3, 2026
- Updated
- Jun 3, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-200
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 3, 2026CVE publishedPublication date reported by the CVE source.
- Jun 3, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- poc_CVE-2026-36611.pyproof of concept · unverified
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Technologies
Your stack
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Your stack
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