CVE-2022-21691 — onionshare-cli
MEDIUMCVE-2022-21691 is a medium-severity (CVSS 4.3) Missing Authentication vulnerability in onionshare-cli. A fix is available for onionshare-cli — see the affected versions and patch details below.
Improper Access Control in Onionshare
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-21691.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2022-21691 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
onionshare-cliReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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-004
- Vulnerability type: Improper Access Control
- Threat level: Moderate
Description:
Chat participants can spoof their channel leave message, tricking others into assuming they left the chatroom.
Technical description:
This series of screenshots show Alice, Bob and Eve joined a chatroom and are the only participants in the chatroom. Eve seemingly leaves the chatroom, which leads Bob and Alice to believe they are having a private chat. The last screenshot shows that Eve only emitted the leave message and is still able to read the chat and possibly write messages.
This can be reproduced by joining the chat with two different instances, where one instance has slightly modified the client-side JavaScript code similar to OTF-003 (page 22). The joined emit needs to be removed from the connect event handler. Therefore the modified client is not listed in the userlist and has no active session. The modified non-listed user also needs to change their username to Eve, which is not shown in the chatroom. The modified client then emits the disconnect event and their connection is no longer usable.
This results in the leave message for Eve and the removal from the user-list but not in removal of the original session of the Eve who announced to join the chat.
Impact:
An adversary with access to the chat environment can spoof his leave event but still persist in the chat with access to all sent messages and the possibility to write in the chat using OTF-003 (page 22).
Recommendation:
- Implement proper session handling
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | onionshare-cli | ≥ 2.3&&< 2.5 | 2.5pip install --upgrade 'onionshare-cli==2.5' |
Affected Products
onionshareonionshareDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for onionshare-cli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update onionshare-cli to 2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-21691 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2022-21691 in your dependencies?
Find it across PyPI, including transitive dependencies.