Answer in brief
CVE-2026-45056 records a Medium severity (CVSS 6.9) vulnerability in Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution. The current sources do not mark it as known exploited. The current feed maps matrix-org/matrix-rust-sdk (generic), matrix-sdk-crypto (rust). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps matrix-org/matrix-rust-sdk (generic), matrix-sdk-crypto (rust). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| matrix-org/matrix-rust-sdkgeneric | >=0.12.0 <0.16.1 | 0.16.1 |
| matrix-sdk-cryptorust | >=0.12.0,<0.16.1 | 0.16.1 |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.