CVE-2026-45056

Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution

Published Sep 11, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

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
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Matrix-org
Matrix-org matrix-rust-sdk
Vendors & Products Matrix-org
Matrix-org matrix-rust-sdk
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 14, 2026, 6:17 PM
Reserved
May 8, 2026, 6:07 PM
Status
Deferred
Published
Sep 11, 2026, 10:16 PM
Modified
Sep 30, 2026, 7:57 PM