CVE-2023-40477
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 · uneditedRARLAB WinRAR Recovery Volume Improper Validation of Array Index Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of RARLAB WinRAR. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the processing of recovery volumes. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-21233.
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 confidenceWinRAR contains a buffer overflow vulnerability in its recovery volume (.rev file) processing logic. The application fails to properly validate array indices when handling user-supplied data in recovery volumes, allowing an attacker to read/write beyond allocated memory boundaries. Successful exploitation enables arbitrary code execution in the context of the current user session.
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< 6.23CVSS 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:3.0/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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Determine installed WinRAR versionOpen WinRAR, click Help > About, or right-click the WinRAR executable (winrar.exe) in the installation directory and select Properties > Details to view the version numberAffected if The displayed version is lower than 6.23 (for example, 6.11, 6.12, 6.20, etc.)
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Identify if recovery volumes are presentSearch for files with the .rev extension in directories where you store or download RAR archives, or check recent downloads for .rev filesAffected if Any .rev recovery volume files exist in your environment that originated from untrusted or unknown sources
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Check if WinRAR automatically opens RAR filesReview your email client settings, browser settings, and Windows file associations to determine if RAR files (including associated .rev files) are set to open automatically upon download or receiptAffected if Automatic opening is enabled and you receive RAR archives with .rev files from untrusted sources via email or web downloads
You are affected if your WinRAR installation is version 6.22 or lower AND you open or process recovery volume (.rev) files, particularly from untrusted sources.
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 · scoped6.23
Update WinRAR to the latest version provided by RARLAB. Until patched, avoid opening recovery volume files from untrusted sources and disable automatic opening of RAR files in email clients or browsers.
WinRAR 6.23
- Download WinRAR 6.23 or later from the official WinRAR website (www.win-rar.com)
- Close any running instances of WinRAR
- Run the installer and follow the prompts to upgrade
- Verify the version by opening WinRAR and checking Help > About WinRAR to confirm version 6.23 or higher is installed
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-40477 — 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-2023-40477 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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