Vulnerability DatabaseCVE-2026-102532
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CVE-2026-102532
Published:October 12, 2026
Updated:October 13, 2026
Impact Via the federation ""/event_auth"" (https://spec.matrix.org/v1.19/server-server-api/#get_matrixfederationv1event_authroomideventid) endpoint, a malicious remote homeserver can query the authorisation events for an event with a given event ID, without needing to be joined to the room. This is only exploitable if the malicious homeserver is joined to some room on the victim homeserver. Homeservers that do not federate or only participate in a closed federation with trusted servers are not affected. ### Patches Update to Synapse 1.157.2 or later. See the table below for patched versions of "Element Server Suite" (https://element.io/en/server-suite), including Long-Term Support (LTS) versions. | | 25.10 LTS | 26.4 LTS | Latest | |:--|--|--|--| | ESS Pro | "25.10.14+lts" | "26.4.9+lts" | "26.7.2" | | ESS Classic | "25.10.09-gui" | "26.04.04-gui" | ⸻ | | ESS Community | ⸻ | ⸻ | "26.7.2" | | ESS TI-Messenger | "25.10.10" | "26.4.5" | "26.7.0" | ### Workarounds None known. ### Identifiers - ELEMENTSEC-2026-1714 ### For more information If you have any questions or comments about this advisory, please email us at "security at element.io" (mailto:security@element.io).
Affected Packages
https://github.com/element-hq/synapse.git (GITHUB):
Affected version(s) >=v1.0.0rc1 <v1.157.2
Fix Suggestion:
Update to version v1.157.2
matrix-synapse (PYTHON):
Affected version(s) >=1.0.0rc1 <1.157.2
Fix Suggestion:
Update to version 1.157.2
Related Resources (3)
https://nvd.nist.gov/vuln/detail/CVE-2026-102532
https://github.com/element-hq/synapse/security/advisories/GHSA-qcjr-46gf-7f4r
https://github.com/element-hq/synapse
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CVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Exposure of Sensitive Information to an Unauthorized Actor
CWE-200