Free practical cybersecurity guidance for organisations without a security team.
hello@actionsoncyber.com
← Back to Vulnerability Briefs

Critical WinRAR Flaw Lets Hackers Run Harmful Code on Windows PCs

A serious security flaw in the Windows version of WinRAR has been found and actively exploited by attackers. This flaw allows hackers to run harmful software by tricking users into opening specially crafted archive files. Since many small businesses use Windows and WinRAR, this vulnerability could put your organisation at risk.

02 June 2026

Reference: CVE-2025-8088

1. What is being reported?

Researchers discovered a weakness in WinRAR for Windows that lets attackers create malicious archive files. When these files are opened, the attacker can run harmful programs on the affected computer without permission.

2. What this means in plain English

If someone in your organisation opens a malicious WinRAR file, hackers could take control of that computer. This could lead to data theft, ransomware, or other damaging attacks. It is important to address this quickly to avoid potential harm.

3. Could this affect a small business?

Any small business or charity using the Windows version of WinRAR could be affected, especially if staff open archive files from unknown or untrusted sources. Organisations not using WinRAR or not on Windows are less likely to be impacted.

4. What to do now

  • Check if WinRAR is installed on your Windows computers and note the version.
  • Ask your IT provider if the current WinRAR version is safe or if an update or patch is available.
  • Avoid opening archive files from unknown or unexpected sources until the issue is resolved.
  • Ensure your antivirus software is up to date and running regular scans.

5. Ask your IT provider

Can you confirm if our Windows computers have a safe version of WinRAR installed, and if not, can you update or remove it to protect us from the recent security flaw CVE-2025-8088?

6. Bottom line

If you use WinRAR on Windows, act promptly to update or secure it to prevent hackers from exploiting this serious flaw.

Information based on CISA KEV, NVD, and reputable security reporting.

Back to Vulnerability Briefs