{"id":"CVE-2024-53867","aliases":["GHSA-56w4-5538-8v8h","PYSEC-2026-1610"],"title":"Synapse Matrix has a partial room state leak via Sliding Sync","summary":"Synapse Matrix has a partial room state leak via Sliding Sync","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","vendor":"matrix-synapse","product":"matrix-synapse","ecosystem":"pip","affected":["matrix-synapse >= 1.113.0rc1, < 1.120.1"],"patched":["matrix-synapse 1.120.1"],"published":"2024-12-03","updated":"2026-07-07","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-56w4-5538-8v8h","references":[{"url":"https://github.com/element-hq/synapse/security/advisories/GHSA-56w4-5538-8v8h"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-53867"},{"url":"https://github.com/matrix-org/matrix-spec-proposals/pull/4186"},{"url":"https://github.com/element-hq/synapse"}],"tags":["osv","pip"],"epss":0.00442,"epssPercentile":0.37752,"ingestedAt":"2026-07-08T18:25:45.796Z","slug":"CVE-2024-53867","body":"## Overview\n\n### 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\n\n## Affected packages\n\n- `matrix-synapse >= 1.113.0rc1, < 1.120.1`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `matrix-synapse 1.120.1`","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}