CVE-2021-33572
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 · uneditedA Denial-of-Service (DoS) vulnerability was discovered in F-Secure Linux Security whereby the FSAVD component used in certain F-Secure products can crash while scanning larger packages/fuzzed files. The exploit can be triggered remotely by an attacker. A successful attack will result in Denial-of-Service (DoS) of the Anti-Virus engine.
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 confidenceA denial-of-service vulnerability exists in F-Secure's FSAVD component where the anti-virus engine crashes when scanning larger packages or fuzzed files. An attacker can trigger this remotely by sending specially crafted large files to be scanned, causing the AV daemon to crash and resulting in denial of service of the entire anti-virus protection.
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 dataall versionsall versionsall versionsall versionsCVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 installed F-Secure productsCheck for installed F-Secure software using package manager (dpkg -l, rpm -qa) or by looking for F-Secure directories in /opt/f-secure or /usr/lib/f-secure. Also check for running F-Secure processes using 'ps aux | grep -i fsecure'Affected if Any of these products are installed: F Secure Cloud Protection For Salesforce, F Secure Elements For Microsoft 365, F Secure Endpoint Protection, or F Secure Linux Security
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Verify FSAVD component is runningCheck for the fsavd or f-secure daemon process using 'ps aux | grep -i fsavd' or 'systemctl list-units | grep -i fsecure'. The vulnerability exists in the FSAVD anti-virus engine componentAffected if The fsavd process is running as a service or daemon on the system
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Confirm real-time or on-access scanning is enabledCheck F-Secure configuration for scanning settings. Look for real-time protection status using 'fsav --version' or check F-Secure configuration files in /etc/f-secure/ or via the management console. The vulnerability triggers when the engine scans incoming filesAffected if Real-time scanning, on-access scanning, or scheduled scanning of files/packages is enabled and processing untrusted files
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Check for crash logs or service failuresReview system logs (/var/log/messages, /var/log/syslog) and F-Secure logs for recent crashes or fsavd service failures. Look for entries containing 'fsavd', 'crash', or 'segfault' related to the antivirus engineAffected if The fsavd daemon has recently crashed or been restarted due to scanning large/fuzzed files
A system is affected if it has any of the listed F-Secure products installed with the FSAVD component active and scanning enabled, as the vulnerability triggers during the scanning of specially crafted large files.
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 dataApply vendor-provided security updates/patches for the affected F-Secure products. Until patches are applied, consider isolating or restricting scanning of untrusted large archives and files to reduce attack surface.
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33572 — 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-2021-33572 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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