CVE-2022-21688: Denial of Service Vulnerability in OnionShare
Summary
CVE-2022-21688: OnionShare is an open source tool that lets you securely and anonymously share files, host websites, and chat with friends using the Tor network. Affects onionshare-cli versions < 2.5. Fixed in 2.5. How to fix ↓
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Background
OnionShare is an open source tool that utilizes the Tor network to securely and anonymously share files, host websites, and chat with friends. It is designed to provide privacy and security for users. However, certain versions of the desktop application are vulnerable to a denial of service attack due to a flaw in the QT image parsing. This vulnerability can be triggered by rendering in the history tab, requiring some user interaction. An attacker with knowledge of the Onion service address can exploit this vulnerability to perform a Denial of Service attack, leading to out-of-memory issues for the server.
Vulnerability Detail
The vulnerability in OnionShare arises from an undisclosed flaw in the QT image parsing. By exploiting this vulnerability, an attacker can trigger a denial of service attack that consumes a significant amount of memory. This can be done by rendering in the history tab of the desktop application. The impact of this vulnerability is elevated as it requires the desktop application with rendered history. An adversary with knowledge of the Onion service address in public mode or with authentication in private mode can quickly exhaust the server's memory, resulting in a denial of service condition. This vulnerability has been patched in version 2.5 of OnionShare.
How To Fix
Latest published version: 2.7.0 as of 22 Oct 2026
pip install --upgrade "onionshare-cli==2.7.0"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.5
This is the first release that contains the fix.
pip install --upgrade "onionshare-cli==2.5"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Conclusion
The denial of service vulnerability in OnionShare can be mitigated by updating to version 2.5 or later. Users are advised to promptly update their OnionShare desktop application to ensure the security and stability of their file sharing, website hosting, and chat activities. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for onionshare-cli →
FAQ
OnionShare is an open source tool that enables secure and anonymous file sharing, website hosting, and chat using the Tor network.
The vulnerability allows an attacker to perform a denial of service attack, leading to out-of-memory issues for the server hosting the OnionShare service.
The vulnerability can be exploited by rendering in the history tab of the OnionShare desktop application, requiring some user interaction.
No specific workaround has been provided for this vulnerability. Users are advised to update to the patched version of OnionShare.
Yes, the vulnerability has been patched in version 2.5 of OnionShare.
References
Related vulnerabilities
Recent vulnerabilities recorded for onionshare-cli.
