Summary
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 theAlice
in 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.
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
CVE-2022-21696 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
- Remove non-visible characters from the username
Frequently Asked Questions
- What is CVE-2022-21696? CVE-2022-21696 is a medium-severity improper input validation vulnerability in onionshare-cli (pip), affecting versions >= 2.3, < 2.5. It is fixed in 2.5. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is CVE-2022-21696? CVE-2022-21696 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of onionshare-cli are affected by CVE-2022-21696? onionshare-cli (pip) versions >= 2.3, < 2.5 is affected.
- Is there a fix for CVE-2022-21696? Yes. CVE-2022-21696 is fixed in 2.5. Upgrade to this version or later.
- Is CVE-2022-21696 exploitable, and should I be worried? Whether CVE-2022-21696 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-21696 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-21696? Upgrade
onionshare-clito 2.5 or later.