CVE-2025-27998
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 · uneditedAn issue in Valvesoftware Steam Client Steam Client 1738026274 allows attackers to escalate privileges via a crafted executable or DLL.
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 · low confidenceThe Steam Client (build 1738026274) contains a privilege escalation vulnerability allowing attackers to execute arbitrary code with elevated privileges through placement of a crafted executable or DLL file. This is characteristic of DLL hijacking or insecure file placement during the application's privilege-elevated operations.
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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/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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Find Steam Client installation pathCheck common installation directories: C:\Program Files (x86)\Steam, C:\Program Files\Steam, or search for steam.exe using: Get-ChildItem -Path "C:\" -Recurse -Filter "steam.exe" -ErrorAction SilentlyContinue | Select-Object -ExpandProperty FullNameAffected if Steam is not installed on the system
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Determine installed Steam versionIf Steam is installed, right-click steam.exe, select Properties, then go to the Details tab to view the Product version. Alternatively, run: (Get-Item "C:\Program Files (x86)\Steam\steam.exe").VersionInfo.ProductVersionAffected if The version matches 1738026274 exactly
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Identify Steam executable loading directoriesCheck the Steam installation folder structure, typically C:\Program Files (x86)\Steam\ or C:\Program Files\Steam\, and look for subdirectories where Steam may load binaries such as bin, steamapps, or the root installation folderAffected if Steam is installed and the directories exist
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Check write permissions on Steam directories for standard usersRun: Get-Acl "C:\Program Files (x86)\Steam" | Format-List to view permissions, or use icacls "C:\Program Files (x86)\Steam\*" to list access control entries. Focus on whether Users or standard accounts have Write or Write+Execute permissionsAffected if Standard (non-admin) users have Write or Write+Execute permissions to any Steam directory that loads executables or DLLs
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Scan for unauthorized executables or DLLs in Steam directoriesRun: Get-ChildItem -Path "C:\Program Files (x86)\Steam" -Recurse -Include *.exe,*.dll | Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-7) } to find recently created or modified binaries, or manually inspect the bin folder for unexpected filesAffected if Unexpected or recently placed executable or DLL files exist in Steam directories
You are affected if you have Steam Client version 1738026274 installed AND standard users have write access to directories where Steam loads executables or DLLs.
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-supplied patches for the Steam Client immediately. Until patched, restrict user write access to Steam installation directories and monitor for unauthorized executables in those locations.
- Consultation3.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,304.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-27998 — 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-2025-27998 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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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.
- 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