Description
matrix-sdk-crypto is a no-network-IO implementation of a state machine that handles end-to-end encryption for Matrix clients. Starting in version 0.12.0 and prior to version 0.17.0, the matrix-sdk-crypto crate was missing a check for the user ID when decrypting an Olm-encrypted event containing the `sender_device_keys` property. This could be exploited to forge an encrypted to-device event, but only if the attacker colludes with the homeserver operator. This issue is fixed in matrix-sdk-crypto 0.17.0. There are no known workarounds for the issue.
Published: 2026-09-11
Score: 6.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-wfq4-36m3-9g42 Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution
History

Fri, 11 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
Description matrix-sdk-crypto is a no-network-IO implementation of a state machine that handles end-to-end encryption for Matrix clients. Starting in version 0.12.0 and prior to version 0.17.0, the matrix-sdk-crypto crate was missing a check for the user ID when decrypting an Olm-encrypted event containing the `sender_device_keys` property. This could be exploited to forge an encrypted to-device event, but only if the attacker colludes with the homeserver operator. This issue is fixed in matrix-sdk-crypto 0.17.0. There are no known workarounds for the issue.
Title Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution
Weaknesses CWE-290
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-11T21:13:56.332Z

Reserved: 2026-05-08T18:07:27.342Z

Link: CVE-2026-45056

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-11T22:16:37.263

Modified: 2026-09-11T22:16:37.263

Link: CVE-2026-45056

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-290

    Authentication Bypass by Spoofing