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Versa Operating SystemOperating system · Versa Networks

CVE-2018-16494

HIGH · 8.8 CVSS v3.1 Published 2021-05-26
Fix available
A fix is available. Upgrade to 16.1r2s11 / 20.2.2 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In VOS and overly permissive "umask" may allow for authorized users of the server to gain unauthorized access through insecure file permissions that can result in an arbitrary read, write, or execution of newly created files and directories. Insecure umask setting was present throughout the Versa servers.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

VOS uses an overly permissive umask setting (likely umask 022 or similar) that creates new files and directories with excessive permissions (e.g., 755 for directories, 644 for files). This allows any authorized local user to read, modify, or execute newly created files they should not have access to, effectively enabling privilege escalation through insecure default file permissions.

MitigationChange the system umask to a restrictive value (such as umask 077) in all relevant configuration files (/etc/profile, /etc/bashrc, application configs) and audit/fix permissions on existing files created with the permissive umask.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Versa Operating SystemOperating system
Affected:< 16.1r2s11>= 20.2.0, < 20.2.2>= 21.1.0, < 21.1.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the VOS version
    Run 'show version' or check /opt/versa/etc/versa.conf for the installed software version string (e.g., 16.1r2, 20.2.1, 21.1.0)
    Affected if The version falls in < 16.1r2s11, >= 20.2.0 and < 20.2.2, or >= 21.1.0 and < 21.1.1
  2. Examine the system umask setting
    Inspect /etc/profile and /etc/bashrc for umask directives. Run 'grep -r umask /etc/profile /etc/bashrc' to find umask values
    Affected if The umask is set to 022 or any value that results in directories with 755 permissions or files with 644 permissions
  3. Verify file permissions on newly created objects
    Create a test directory and file (mkdir /tmp/test_perms && touch /tmp/test_perms/file), then run 'ls -ld /tmp/test_perms' and 'ls -l /tmp/test_perms/file' to check actual permissions
    Affected if The directory shows 755 (rwxr-xr-x) or the file shows 644 (rw-r--r--)
  4. Check application-specific umask in VOS config
    Look for umask settings in /opt/versa/etc/ or /config/versa directories in Versa-specific configuration files
    Affected if Any Versa application config sets umask to a permissive value like 022

If the VOS version is within the affected ranges AND the system or application umask is set to a permissive value (022 or similar) that results in directories with 755 and files with 644 permissions, the system is vulnerable.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 16.1r2s11 / 20.2.2 / 21.1.1 or later
Fixed in 16.1r2s1120.2.221.1.1
Interim mitigation

Change the system umask to a restrictive value (such as umask 077) in all relevant configuration files (/etc/profile, /etc/bashrc, application configs) and audit/fix permissions on existing files created with the permissive umask.

Recommended fix High confidence

16.1r2s11, 20.2.2, or 21.1.1 (depending on your current major version branch)

  1. 1. Identify the currently installed Versa Operating System version using 'show version' or 'admin show system information'
  2. 2. Determine which upgrade path applies based on current version (16.1.x, 20.2.x, or 21.1.x branch)
  3. 3. Download the appropriate fixed release: 16.1r2s11 or later, 20.2.2 or later, or 21.1.1 or later from Versa Networks support portal
  4. 4. Schedule a maintenance window as upgrades require system downtime
  5. 5. Back up current configuration using 'request system backup'
  6. 6. Upload the new software image to the Versa device
  7. 7. Perform the upgrade using 'request system software install <filename>'
  8. 8. Reboot the system after installation completes
Caveat Standard upgrade risks apply - test in staging environment first; some legacy configurations may need adjustment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Versa Operating System Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-16494 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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