{"id":"CVE-2022-39251","aliases":["GHSA-r48r-j8fx-mq2c"],"url":"https://o3.security/vulnerability/CVE-2022-39251","summary":"Matrix Javascript SDK vulnerable to Olm/Megolm protocol confusion","details":"Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver can construct messages that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. Starting with version 19.7.0, matrix-js-sdk has been modified to only accept Olm-encrypted to-device messages. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.","published":"2022-09-28T00:00:00Z","modified":"2026-07-15T01:49:01.445810772Z","cvss":{"score":8.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"matrix-js-sdk","fixedVersion":"19.7.0"}],"fix":{"url":"https://github.com/matrix-org/matrix-js-sdk/commit/a587d7c36026fe1fcf93dfff63588abee359be76","label":"matrix-org/matrix-js-sdk@a587d7c"},"references":[{"type":"WEB","url":"https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.7.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39251.json"},{"type":"ADVISORY","url":"https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-r48r-j8fx-mq2c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-39251"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202210-35"},{"type":"FIX","url":"https://github.com/matrix-org/matrix-js-sdk/commit/a587d7c36026fe1fcf93dfff63588abee359be76"},{"type":"ARTICLE","url":"https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:01.445810772Z"}}