{"id":"PYSEC-2026-1610","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","aliases":["CVE-2024-53867","GHSA-56w4-5538-8v8h"],"modified":"2026-07-07T17:47:03.468918922Z","published":"2026-07-07T14:34:46.676923Z","references":[{"type":"WEB","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":"WEB","url":"https://github.com/matrix-org/matrix-spec-proposals/pull/4186"},{"type":"PACKAGE","url":"https://github.com/element-hq/synapse"},{"type":"PACKAGE","url":"https://pypi.org/project/matrix-synapse"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-56w4-5538-8v8h"}],"affected":[{"package":{"name":"matrix-synapse","ecosystem":"PyPI","purl":"pkg:pypi/matrix-synapse"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.113.0rc1"},{"fixed":"1.120.1"}]}],"versions":["1.113.0","1.113.0rc1","1.114.0","1.114.0rc1","1.114.0rc3","1.115.0","1.115.0rc1","1.115.0rc2","1.116.0","1.116.0rc1","1.116.0rc2","1.117.0","1.117.0rc1","1.118.0","1.118.0rc1","1.119.0","1.119.0rc2","1.120.0","1.120.0rc1"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/matrix-synapse/PYSEC-2026-1610.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"}]}