What’s Vulnerable › Vulnerabilities

CVE-2022-21689: Denial of Service in Onionshare

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-01-18 · updated 2026-06-17
• Weakness: CWE-400

Description

OnionShare is an open source tool that lets you securely and anonymously share files, host websites, and chat with friends using the Tor network. In affected versions the receive mode limits concurrent uploads to 100 per second and blocks other uploads in the same second, which can be triggered by a simple script. An adversary with access to the receive mode can block file upload for others. There is no way to block this attack in public mode due to the anonymity properties of the tor network.

Affected products

• onionshare: before 2.5 — fixed in 2.5

How to fix

Upgrade to a fixed version: onionshare 2.5. Check the vendor advisory for mitigations.

References

• https://github.com/onionshare/onionshare/releases/tag/v2.5
• https://github.com/onionshare/onionshare/security/advisories/GHSA-jh82-c5jw-pxpc
• https://github.com/onionshare/onionshare/releases/tag/v2.5
• https://github.com/onionshare/onionshare/security/advisories/GHSA-jh82-c5jw-pxpc

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