{"id":"CVE-2024-53867","aliases":["GHSA-56w4-5538-8v8h","PYSEC-2026-1610"],"url":"https://o3.security/vulnerability/CVE-2024-53867","summary":"Synapse Matrix has a partial room state leak via Sliding Sync","details":"### Impact\nThe Sliding Sync feature on Synapse versions between 1.113.0rc1 and 1.120.0 can leak partial room state changes to users no longer in a room. Non-state events, like messages, are unaffected.\n\n### Patches\nSynapse version 1.120.1 fixes the problem.\n\n### Workarounds\nDisable Sliding Sync.\n\n### References\nhttps://github.com/matrix-org/matrix-spec-proposals/pull/4186\nhttps://github.com/element-hq/synapse/blob/d80cd57c54427687afcb48740d99219c88a0fff1/synapse/config/experimental.py#L341-L344\n\n### For more information\n\nIf you have any questions or comments about this advisory, please email us at [security at element.io](mailto:security@element.io).\n","published":"2024-12-03T16:52:01.596Z","modified":"2026-10-28T02:30:37.596927855Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"matrix-synapse","fixedVersion":"1.120.1"}],"fix":{"url":"https://github.com/matrix-org/matrix-spec-proposals/pull/4186","label":"matrix-org/matrix-spec-proposals#4186"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/53xxx/CVE-2024-53867.json"},{"type":"ADVISORY","url":"https://github.com/element-hq/synapse/security/advisories/GHSA-56w4-5538-8v8h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-53867"},{"type":"FIX","url":"https://github.com/matrix-org/matrix-spec-proposals/pull/4186"},{"type":"PACKAGE","url":"https://github.com/element-hq/synapse"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:37.596927855Z"}}