Root shell access via unrestricted BusyBox exec
Published Apr 17, 2024 · Updated Nov 4, 2025
Command injection in /bin/login in Peplink Smart Reader 1.2.0 allows physically proximate attackers to obtain a root shell via serial console. The custom login launches iotsh for a hard-coded iot account, but its BusyBox applet filter leaves exec available to run /bin/sh. Physical serial-console access is required; successful exploitation escapes the restricted shell and grants unrestricted root capabilities.
Summary
What happened
Command injection in /bin/login in Peplink Smart Reader 1.2.0 allows physically proximate attackers to obtain a root shell via serial console. The custom login launches iotsh for a hard-coded iot account, but its BusyBox applet filter leaves exec available to run /bin/sh. Physical serial-console access is required; successful exploitation escapes the restricted shell and grants unrestricted root capabilities.
The record
- CVE
- CVE-2023-40146
- Published
- Apr 17, 2024
- Updated
- Nov 4, 2025
- Vendor
- Peplink
- Product
- Smart Reader
- Classifications
- CWE-77, CWE-798, T1059.004
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 17, 2024CVE publishedPublication date reported by the CVE source.
- Nov 4, 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=v1.2.0
- Affected versionversion=v1.2.0 (in QEMU)
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
- Cisco Talos Smart Reader serial-console shell-escape procedurefunctional · demonstrated
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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