dbcve.org
Client SecurityApplication · Withsecure

CVE-2023-42520

HIGH · 7.5 CVSS v3.1 Published 2023-09-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
Certain WithSecure products allow a remote crash of a scanning engine via unpacking of crafted data files. This affects WithSecure Client Security 15, WithSecure Server Security 15, WithSecure Email and Server Security 15, WithSecure Elements Endpoint Protection 17 and later, WithSecure Client Security for Mac 15, WithSecure Elements Endpoint Protection for Mac 17 and later, Linux Security 64 12.0 , Linux Protection 12.0, and WithSecure Atlant (formerly F-Secure Atlant) 1.0.35-1.

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

WithSecure security products contain a vulnerability in their scanning engine's data file unpacking functionality that allows remote attackers to cause a denial of service (crash) via specially crafted data files. The vulnerability affects multiple product lines including Client Security, Server Security, Elements Endpoint Protection, and Linux Security products.

MitigationApply vendor-provided patches or updates to affected WithSecure products. Since this is a scanning engine crash vulnerability, prioritize patching production scanning engines to restore protection capabilities.

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
Client SecurityApplication
Affected:= 15
Elements Endpoint ProtectionApplication
Affected:>= 17
Email And Server SecurityApplication
Affected:= 15
Server SecurityApplication
Affected:= 15
Linux ProtectionApplication
Affected:= 12.0
Linux Security 64Application
Affected:= 12.0
AtlantApplication
Affected:= 1.0.35-1

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

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

  1. Identify installed WithSecure product
    On Windows, check Programs and Features or registry key HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall for WithSecure entries. On Linux, run 'rpm -qa | grep -i fsecure' or 'dpkg -l | grep -i fsecure' to list installed WithSecure packages.
    Affected if a WithSecure security product is present on the system
  2. Determine product version on Windows
    For Client Security, Server Security, or Elements Endpoint Protection: open Control Panel > Programs and Features, right-click the WithSecure product, select Properties, and note the Version field. Alternatively, check the registry under HKLM\Software\WithSecure or the installation directory for a version file.
    Affected if the product version cannot be determined or differs from the vendor's current version
  3. Determine product version on Linux
    For Linux Protection or Linux Security 64: run 'fsecure --version' or 'fspamd --version' if available. Otherwise, use 'rpm -qi f-secure-linux-security' or 'dpkg -s f-secure-linux-security' to query package version.
    Affected if the product version cannot be determined or differs from the vendor's current version
  4. Compare version against affected ranges
    Match your identified product and version to the affected list: Client Security version 15, Elements Endpoint Protection version 17+, Email and Server Security version 15, Server Security version 15, Linux Protection version 12.0, Linux Security 64 version 12.0, or Atlant version 1.0.35-1.
    Affected if the installed version exactly matches one of the affected versions listed in the CVE

You are affected if a WithSecure product is installed and its version exactly matches 15, 17+, or 12.0 for the products listed in the CVE.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-provided patches or updates to affected WithSecure products. Since this is a scanning engine crash vulnerability, prioritize patching production scanning engines to restore protection capabilities.

Fix this in Client Security Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-42520 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-42520 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data