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Client SecurityApplication · Withsecure

CVE-2023-42523

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 a PE file. 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 · high confidence

A denial of service vulnerability exists in WithSecure's scanning engine where processing a specially crafted PE (Portable Executable) file during unpacking causes the engine to crash. The vulnerability is remotely exploitable through the product's file scanning functionality, allowing an attacker to crash the scanning engine by delivering a malicious PE file.

MitigationApply vendor-provided patches or updates to affected WithSecure products. Until patched, consider implementing additional file-type filtering at email/web gateways to block potentially malicious PE attachments.

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
    Check the installed WithSecure security product on the system. This can be done via the Add/Remove Programs list, the installed applications inventory, or by checking the product service name in Services.msc. Look for product names such as WithSecure Client Security, WithSecure Elements Endpoint Protection, WithSecure Email And Server Security, WithSecure Server Security, WithSecure Linux Protection, WithSecure Linux Security 64, or WithSecure Atlant.
    Affected if No WithSecure product is installed - the system is not affected.
  2. Determine the installed WithSecure product version
    Using the identified product, check its version. This is typically available in the product's About or Help section, in the Windows Programs and Features list, or via the product's command-line interface if available. For Linux products, check the RPM/DEB package version using the system's package manager (e.g., rpm -qi withsecure or dpkg -l | grep withsecure).
    Affected if The installed version matches one of the affected versions: Client Security 15, Elements Endpoint Protection 17+, Email And Server Security 15, Server Security 15, Linux Protection 12.0, Linux Security 64 12.0, or Atlant 1.0.35-1.
  3. Verify the scanning engine is enabled
    Check that the real-time or on-demand scanning engine is active and enabled. This can be verified through the product's status interface, its system tray icon status, or by checking that the scanning service/process is running. Look for services related to the scanning engine or real-time protection.
    Affected if The scanning engine is disabled or not running - the vulnerability is not currently exploitable.
  4. Confirm PE file scanning is active
    Verify that the product is configured to scan PE (Portable Executable) files. Check the scanning or file type filtering settings within the product's configuration. Ensure that the unpacking/decompression scanning feature for executable files is enabled.
    Affected if PE file scanning and unpacking are disabled - the specific attack vector is not available.

A system is affected if it runs an affected WithSecure product version (15, 17+, 12.0, or 1.0.35-1 depending on the product) AND has the scanning engine enabled with PE file unpacking support active.

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. Until patched, consider implementing additional file-type filtering at email/web gateways to block potentially malicious PE attachments.

Fix this in Client Security Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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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-2023-42523 in production — separate from our analysis above.

No notes yet

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