{"cve":"CVE-2022-39254","nvd":{"published":"2022-09-29T15:15:10.513","modified":"2026-06-17T04:58:00.400","status":"Modified","description":"matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","score":6.5},"cwes":["CWE-287","CWE-322"],"references":["https://github.com/poljar/matrix-nio/commit/b1cbf234a831daa160673defd596e6450e9c29f0","https://github.com/poljar/matrix-nio/security/advisories/GHSA-w4pr-4vjg-hffh","https://github.com/poljar/matrix-nio/commit/b1cbf234a831daa160673defd596e6450e9c29f0","https://github.com/poljar/matrix-nio/security/advisories/GHSA-w4pr-4vjg-hffh"],"products":["matrix-nio_project:matrix-nio"],"source":"nvd","synced_at":"2026-10-19T21:36:05.460296998+00:00"},"epss":{"cve":"CVE-2022-39254","score":0.00678,"percentile":0.52336,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-w4pr-4vjg-hffh","url":"https://osv.dev/vulnerability/GHSA-w4pr-4vjg-hffh","summary":"When matrix-nio receives forwarded room keys, the receiver doesn't check if it requested the key from the forwarder","modified":"2026-07-07T11:56:11.195093339Z","packages":[{"ecosystem":"PyPI","name":"matrix-nio","purl":"pkg:pypi/matrix-nio","ranges":["<0.20"],"fixed":["0.20"]}]},{"id":"PYSEC-2026-842","url":"https://osv.dev/vulnerability/PYSEC-2026-842","summary":"When matrix-nio receives forwarded room keys, the receiver doesn't check if it requested the key from the forwarder","modified":"2026-07-07T11:46:05.855618817Z","packages":[{"ecosystem":"PyPI","name":"matrix-nio","purl":"pkg:pypi/matrix-nio","ranges":["<0.20"],"fixed":["0.20"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}