PYSEC-2026-1610

Vulnerability from pysec - Published: 2026-07-07 14:34 - Updated: 2026-07-07 17:24
VLAI
Details

Impact

The 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.

Patches

Synapse version 1.120.1 fixes the problem.

Workarounds

Disable Sliding Sync.

References

https://github.com/matrix-org/matrix-spec-proposals/pull/4186 https://github.com/element-hq/synapse/blob/d80cd57c54427687afcb48740d99219c88a0fff1/synapse/config/experimental.py#L341-L344

For more information

If you have any questions or comments about this advisory, please email us at security at element.io.

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Impacted products
Name purl
matrix-synapse pkg:pypi/matrix-synapse
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse",
        "purl": "pkg:pypi/matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.113.0rc1"
            },
            {
              "fixed": "1.120.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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"
      ]
    }
  ],
  "aliases": [
    "CVE-2024-53867",
    "GHSA-56w4-5538-8v8h"
  ],
  "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",
  "id": "PYSEC-2026-1610",
  "modified": "2026-07-07T17:24:38.563328Z",
  "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"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Synapse Matrix has a partial room state leak via Sliding Sync"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.