What’s Vulnerable › Vulnerabilities

CVE-2026-45056: Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution

• Severity: medium (CVSS 6.9 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-11 · updated 2026-09-30
• Weakness: CWE-290

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.

Affected products

• matrix-org matrix-rust-sdk: from 0.12.0, < 0.16.1

References

• https://github.com/matrix-org/matrix-rust-sdk/pull/6553
• https://github.com/matrix-org/matrix-rust-sdk/releases/tag/matrix-sdk-0.16.1
• https://github.com/matrix-org/matrix-rust-sdk/security/advisories/GHSA-wfq4-36m3-9g42
• https://rustsec.org/advisories/RUSTSEC-2026-0159.html

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