Username spoofing in OnionShare
Between September 26, 2021 and October 8, 2021, Radically Open Security conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's Red Team lab. This is an issue from that penetration test.
- Vulnerability ID: OTF-005
- Vulnerability type: Improper Input Sanitization
- Threat level: Low
Description:
It is possible to change the username to that of another chat participant with an additional space character at the end of the name string.
Technical description:
Assumed users in Chat:
- Alice
- Bob
- Mallory
- Mallory renames to
Alice. - Mallory sends message as
Alice. - Alice and Bob receive a message from Mallory disguised as
Alice, which is hard to distinguish from theAlicein the web interface.
Other (invisible) whitespace characters were found to be working as well.
Impact:
An adversary with access to the chat environment can use the rename feature to impersonate other participants by adding whitespace characters at the end of the username.
Recommendation:
- Remove non-visible characters from the username
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | onionshare-cli | >= 2.3, < 2.5 | 2.5 |
References
- https://github.com/onionshare/onionshare/security/advisories/GHSA-68vr-8f46-vc9f
- https://github.com/onionshare/onionshare/releases/tag/v2.5
- https://nvd.nist.gov/vuln/detail/CVE-2022-21696
- https://github.com/onionshare/onionshare
- https://github.com/pypa/advisory-database/tree/main/vulns/onionshare-cli/PYSEC-2022-47.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-20- Platform
- Python (PyPI)
- Package
onionshare-cli- Disclosed
- 18.01.2022
- Updated
- 11.10.2026 11:20
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2022-47 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-68vr-8f46-vc9f - CC BY 4.0
Vulnerability history: onionshare-cli
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 13
- First → latest
- 11.2021 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 2
- Medium 10
Disclosures per year
- 2021: 2
- 2022: 9
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 2
-
Username spoofing in OnionShare this entry
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