RARLAB WinRAR: file access flaw under attack

What is affected

RARLAB WinRAR is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

RARLAB WinRAR contains a path traversal vulnerability affecting the Windows version of WinRAR. This vulnerability could allow an attacker to execute arbitrary code by crafting malicious archive files.

What an attacker can do

This is a file access flaw. It lets an attacker read or write files they should never reach, such as configuration files that hold passwords, or upload a malicious file that the system then runs.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

No account needed

Does the victim have to do something?

Yes, the victim must take a specific action

CISA records this vulnerability as known to be used in ransomware campaigns: attackers use it to get in, then encrypt files and demand payment.

What to do

1. Update RARLAB WinRAR now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• win-rar.comwww.win-rar.com/singlenewsview.html?&L=0&tx_ttnews%5Btt_news%5D=283&cHash=a64b4a8f662d3639

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on August 12, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by September 2, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 94% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.9% of all scored vulnerabilities.

Its CVSS severity score is 8.4 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

A path traversal vulnerability affecting the Windows version of WinRAR allows the attackers to execute arbitrary code by crafting malicious archive files. This vulnerability was exploited in the wild and was discovered by Anton Cherepanov, Peter Košinár, and Peter Strýček from ESET.