CVE-2025-45311
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 · uneditedInsecure permissions in fail2ban-client v0.11.2 allows attackers with limited sudo privileges to perform arbitrary operations as root. NOTE: this is disputed by multiple parties because the action for a triggered rule can legitimately be an arbitrary operation as root. Thus, the software is behaving in accordance with its intended privilege model.
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 confidenceInsecure permissions in fail2ban-client v0.11.2 allows attackers with limited sudo privileges to perform arbitrary operations as root. However, this is disputed as the software is functioning as designed - fail2ban legitimately executes arbitrary operations as root when ban actions are triggered.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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 checksWork through these to decide whether this CVE applies to you.
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Identify fail2ban-client versionRun 'fail2ban-client --version' or check the installed package version via your package manager (dpkg -l fail2ban, rpm -qi fail2ban, etc.)Affected if The version is exactly 0.11.2
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Check for sudo access to fail2ban-clientRun 'sudo -l' as the unprivileged user in question to list permitted commands, or inspect /etc/sudoers and /etc/sudoers.d/ for fail2ban entriesAffected if The user has sudo privileges configured for fail2ban-client or fail2ban commands
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Review configured ban actionsExamine fail2ban configuration files in /etc/fail2ban/ (particularly jail.conf, jail.local, and action/*.conf) to identify which action scripts are executed on bansAffected if Custom or unrestricted action scripts are defined that could execute arbitrary commands as root
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Verify action script permissionsList the action scripts referenced in your fail2ban configuration (typically in /etc/fail2ban/action.d/) and check their ownership and permissions with 'ls -la'Affected if Action scripts are writable by the sudo-capable user or group
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Audit sudoers for fail2ban command restrictionsReview sudoers entries for fail2ban to determine if command arguments are restricted or if the user can pass arbitrary arguments (e.g., 'sudo fail2ban-client' vs 'sudo fail2ban-client set')Affected if The sudoers configuration allows unrestricted command execution or argument injection
A user is affected if they have sudo privileges to fail2ban-client on version 0.11.2 and can leverage those privileges to execute arbitrary commands as root through action scripts.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataSince this is disputed as working as intended, remediation should focus on restricting sudo access to fail2ban commands and documenting the intended privilege model. Consider using fail2ban's action framework with constrained command whitelisting.
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-45311 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-45311 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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