Vulnerability record · CVE-2023-38831 · published 23 August 2023
CVE-2023-38831: WinRAR ZIP archive spoofing leads to arbitrary code execution
Rarlab · Winrar
WinRAR before 6.23 mishandles ZIP archives that contain a benign file and a folder with the same name, causing the folder's contents to be processed when the user opens only the benign file. This lets a crafted archive run executable content under the user's context. It was exploited in the wild from April through October 2023.
Description
RARLAB WinRAR before 6.23 allows attackers to execute arbitrary code when a user attempts to view a benign file within a ZIP archive. The issue occurs because a ZIP archive may include a benign file (such as an ordinary .JPG file) and also a folder that has the same name as the benign file, and the contents of the folder (which may include executable content) are processed during an attempt to access only the benign file. This was exploited in the wild in April through October 2023.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Automated analysis
critical priorityActively exploited in the wild, listed in CISA KEV with known ransomware use, and has a very high EPSS score.
What it is
WinRAR before 6.23 mishandles ZIP archives that contain a benign file and a folder with the same name, causing the folder's contents to be processed when the user opens only the benign file. This lets a crafted archive run executable content under the user's context. It was exploited in the wild from April through October 2023.
Impact
An attacker can execute arbitrary code with the privileges of the user who opens the archive, leading to full compromise of that user's data and session. CISA KEV notes known ransomware campaign use.
Attack surface
Reached locally when a user opens or views a file inside a malicious ZIP archive; the CVSS vector requires user interaction (UI:R) and no privileges (PR:N). No authentication is needed.
Exploitation
Exploited in the wild per the description and CISA KEV (added 2023-08-24), with multiple references tagged Exploit. EPSS 30-day probability is 0.98022 (99.9th percentile).
What to do
- Upgrade WinRAR to 6.23 or later immediately.
- If upgrade is not possible, discontinue use of WinRAR per CISA KEV required action.
- Block or quarantine ZIP archives from untrusted sources at email and web gateways.
- Warn users not to open files inside archives from unknown senders.
Detection
- Monitor for WinRAR spawning child processes such as cmd.exe, powershell.exe, wscript.exe or mshta.exe.
- Alert on archive files containing a file and a same-named folder with executable content inside.
- Hunt for process creation where WinRAR.exe is the parent of a script or shell interpreter.
- Review endpoint logs for file writes to temp or startup locations following archive open events.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Exploitation in the wild
CISA added CVE-2023-38831 to the Known Exploited Vulnerabilities catalog on 24 August 2023 as "RARLAB WinRAR Code Execution Vulnerability". CISA reports known use in ransomware campaigns. Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Federal deadline 14 September 2023.
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2023-38831 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2023-38831), CISA KEV, FIRST EPSS (scores of 2026-09-24). This page is refreshed as NVD updates the record.
