{"id":"CVE-2022-21695","aliases":["GHSA-99p8-9p2c-49j4","PYSEC-2022-46"],"url":"https://o3.security/vulnerability/CVE-2022-21695","summary":"Improper Access Control in Onionshare","details":"Between September 26, 2021 and October 8, 2021, [Radically Open Security](https://www.radicallyopensecurity.com/) conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's [Red Team lab](https://www.opentech.fund/labs/red-team-lab/). This is an issue from that penetration test.\n\n- Vulnerability ID: OTF-009\n- Vulnerability type: Improper Access Control\n- Threat level: Low\n\n## Description:\n\nAuthenticated users (or unauthenticated in public mode) can send messages without being visible in the list of chat participants.\n\n## Technical description:\n\nPrerequisites:\n\n- Existing chatroom\n- Access to the chatroom (Public or known Private Key)\n- Either a modified frontend client or manual requests from burp/curl\n\nIf a user opens the chatroom without emitting the join message he will not be present in session.users[x] list. Therefore there is no listing in the frontend and no chat participant knows another party joined the chat. It is still possible to send messages in the chatroom.\n\nIf a user decides to abuse OTF-003 (page 22) he can impersonate messages from existing users; others would not be able to distinguish original and faked messages. This is also a prerequisite for OTF-004 (page 19).\n\n## Impact:\n\nAn adversary with access to the chat environment can send messages to the chat without being visible in the list of chat participants.\n\n## Recommendation:\n\n- Allow chat access only after emission of the join event.\n- Implement proper session handling.","published":"2022-01-18T21:55:10Z","modified":"2026-08-12T03:51:16.175022082Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"onionshare-cli","fixedVersion":"2.5"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/onionshare/onionshare/releases/tag/v2.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/21xxx/CVE-2022-21695.json"},{"type":"ADVISORY","url":"https://github.com/onionshare/onionshare/security/advisories/GHSA-99p8-9p2c-49j4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-21695"},{"type":"PACKAGE","url":"https://github.com/onionshare/onionshare"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/onionshare-cli/PYSEC-2022-46.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:16.175022082Z"}}