CVE-2018-20250
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 · uneditedIn WinRAR versions prior to and including 5.61, There is path traversal vulnerability when crafting the filename field of the ACE format (in UNACEV2.dll). When the filename field is manipulated with specific patterns, the destination (extraction) folder is ignored, thus treating the filename as an absolute path.
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 confidencePath traversal vulnerability in WinRAR's UNACEV2.dll when parsing ACE archive files. By crafting a malicious ACE file with a filename field containing absolute path patterns (e.g., starting with drive letter or absolute path), the extraction process ignores the destination folder and writes files to attacker-controlled locations on the system.
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<= 5.61CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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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Locate WinRAR installationSearch for winrar.exe in common installation directories such as C:\Program Files\WinRAR or C:\Program Files (x86)\WinRAR, or use the Windows search feature to find the executable.Affected if WinRAR is found on the system
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Determine installed WinRAR versionRight-click on winrar.exe, select Properties, and view the Details tab to see the File Version. Alternatively, open WinRAR, click Help > About and note the version number displayed.Affected if The version number is 5.61 or lower
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Check for vulnerable UNACEV2.dllNavigate to the WinRAR installation directory (where winrar.exe is located) and look for a file named UNACEV2.dll.Affected if The file UNACEV2.dll exists in the WinRAR installation folder
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Verify ACE archive support is availableAttempt to open or test an ACE format archive file using WinRAR, or check if ACE appears in the list of supported formats when opening an archive.Affected if WinRAR can process ACE format archives due to the presence of UNACEV2.dll
The system is affected if WinRAR version 5.61 or lower is installed with the UNACEV2.dll component present, allowing ACE archive extraction that could enable arbitrary file write via path traversal.
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.
dbcve · scopedUpgrade WinRAR to version 5.61 or later, or remove the vulnerable UNACEV2.dll component from the WinRAR installation directory to prevent ACE file processing.
WinRAR 5.70 or later
- Download WinRAR 5.70 or later from the official vendor website (rarlab.com)
- Uninstall the current version of WinRAR 5.61 or earlier
- Install the downloaded WinRAR 5.70 or later version
- Verify the installation was successful by checking WinRAR > Help > About
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 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 $1,744.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20250 — 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-2018-20250 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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