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Nagios XiApplication · Nagios

CVE-2011-10035

HIGH · 7.0 CVSS v3.1 Published 2025-10-30
Fix available
A fix is available. Upgrade to after 2009 or later.
See remediation →
72/100
Remediation priority · Elevated
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
Nagios XI versions prior to 2011R1.9 contain privilege escalation vulnerabilities in the scripts that install or update system crontab entries. Due to time-of-check/time-of-use race conditions and missing synchronization or final-path validation, a local low-privileged user could manipulate filesystem state during crontab installation to influence the files or commands executed with elevated privileges, resulting in execution with higher privileges.

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 · high confidence

Nagios XI versions prior to 2011R1.9 contain TOCTOU race conditions in crontab installation scripts. A local low-privileged user can manipulate filesystem state during the window between permission checks and file operations to inject malicious content into commands that execute with elevated (root) privileges, achieving privilege escalation.

MitigationUpgrade to Nagios XI 2011R1.9 or later, which includes proper synchronization and final-path validation in crontab installation scripts.

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
Nagios XiApplication
Affected:<= 2009= 2011

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
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/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 installed Nagios XI version
    Run: cat /usr/local/nagiosxi/etc/xiversion.txt or check the Nagios XI admin interface under 'About' page
    Affected if Version is 2009, 2010, 2011, or any version prior to 2011R1.9
  2. Locate crontab installation scripts
    Search for scripts in /usr/local/nagiosxi/scripts/ or /etc/cron.d/nagiosxi related to crontab installation. Common files: installcrontab.sh, nagiosxi.cron, or similar
    Affected if Scripts exist and their modification timestamps predate the 2011R1.9 release
  3. Inspect crontab script for TOCTOU vulnerable code patterns
    Examine the installation scripts for sequences where file permissions are checked (using test, [ -w ], or stat) before file operations (cp, mv, chown) without atomic operations or locking
    Affected if Scripts show separate permission check commands followed by file manipulation commands without flock, atomic operations, or final-path validation between them
  4. Check filesystem permissions on cron directories
    Run: ls -la /etc/cron.d/ and ls -la /var/spool/cron/ to verify if low-privileged users have write access to parent directories where cron files are placed
    Affected if World-writable directories exist in the cron file deployment path allowing unprivileged users to manipulate files during the race window
  5. Verify if cron jobs run as root
    Check crontab entries: crontab -l -u root or cat /etc/cron.d/nagios* to see which user executes the Nagios XI cron tasks
    Affected if Cron jobs execute as root and the installation script lacks proper synchronization between check and write operations

The environment is affected if Nagios XI version is 2011R1.8 or earlier AND crontab installation scripts contain non-atomic permission-check-then-file-operate sequences that allow filesystem manipulation by local users.

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 a release after 2009
Interim mitigation

Upgrade to Nagios XI 2011R1.9 or later, which includes proper synchronization and final-path validation in crontab installation scripts.

Recommended fix High confidence

Nagios XI 2011R1.9 or later

  1. Back up the existing Nagios XI installation and configuration files before proceeding with the upgrade
  2. Download Nagios XI version 2011R1.9 or later from the official Nagios website (www.nagios.com)
  3. Consult the official Nagios XI upgrade documentation for the specific upgrade procedure
  4. Execute the upgrade following the documented steps, ensuring the crontab installation scripts are updated
  5. After upgrade, verify the crontab entries are properly secured and owned by root
  6. Confirm the fix by checking that the vulnerable race condition in crontab installation scripts has been addressed in the new version
Caveat Review Nagios XI release notes for any configuration changes or migration requirements between versions before upgrading

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

Fix this in Nagios Xi Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2011-10035 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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