Configuration-file disclosure via improper Quagga validation
Published Nov 28, 2023 · Updated Jun 5, 2025
Improper input validation in affected Zyxel firewall firmware allows local authenticated users to read configuration files. The flaw resides in the bundled Quagga package, but Zyxel has not disclosed which input is accepted without validation or how it reaches configuration files. Exploitation requires authenticated local access to the appliance and exposes stored configuration data without reported write or service-interruption impact.
Summary
What happened
Improper input validation in affected Zyxel firewall firmware allows local authenticated users to read configuration files. The flaw resides in the bundled Quagga package, but Zyxel has not disclosed which input is accepted without validation or how it reaches configuration files. Exploitation requires authenticated local access to the appliance and exposes stored configuration data without reported write or service-interruption impact.
The record
- CVE
- CVE-2023-35136
- Published
- Nov 28, 2023
- Updated
- Jun 5, 2025
- Vendor
- Zyxel Networks
- Product
- Zyxel USG FLEX 50(W) Series Firmware
- Classifications
- CWE-20, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 28, 2023CVE publishedPublication date reported by the CVE source.
- Jun 5, 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=versions 4.16 through 5.37
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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