Cross-boundary file access via unchecked sendmail arguments
Published Jan 22, 2024 · Updated May 30, 2025
External path control in CloudLinux CageFS 7.0.8-2 and earlier allows local users to read and write files outside their cages. The default sendmail proxy passes unchecked -bi and -oA arguments outside CageFS, letting Postfix treat attacker-chosen paths as alias databases. A CageFS-restricted account on a Postfix-backed host is sufficient; readable and writable content is limited to supported alias database formats.
Summary
What happened
External path control in CloudLinux CageFS 7.0.8-2 and earlier allows local users to read and write files outside their cages. The default sendmail proxy passes unchecked -bi and -oA arguments outside CageFS, letting Postfix treat attacker-chosen paths as alias databases. A CageFS-restricted account on a Postfix-backed host is sufficient; readable and writable content is limited to supported alias database formats.
The record
- CVE
- CVE-2020-36772
- Published
- Jan 22, 2024
- Updated
- May 30, 2025
- Vendor
- CloudLinux
- Product
- CageFS
- Classifications
- CWE-610, CWE-73, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 22, 2024CVE publishedPublication date reported by the CVE source.
- May 30, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.0.8-2
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
- SBA CageFS sendmail proxy proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo