---
id: CVE-2026-45056
title: >-
  matrix-sdk-crypto is a no-network-IO implementation of a state machine that
  handles end-to-end encryption for Matrix clients
summary: >-
  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…
severity: medium
cvss: 6.9
cvssVector: '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'
cwe:
  - CWE-290
vendor: matrix-org
product: matrix-rust-sdk
affected:
  - 'matrix-rust-sdk >= 0.12.0, < 0.16.1'
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T19:17:22.060'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45056'
references:
  - url: 'https://github.com/matrix-org/matrix-rust-sdk/pull/6553'
    label: security-advisories@github.com
  - url: >-
      https://github.com/matrix-org/matrix-rust-sdk/releases/tag/matrix-sdk-0.16.1
    label: security-advisories@github.com
  - url: >-
      https://github.com/matrix-org/matrix-rust-sdk/security/advisories/GHSA-wfq4-36m3-9g42
    label: security-advisories@github.com
  - url: 'https://rustsec.org/advisories/RUSTSEC-2026-0159.html'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45056.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-45056'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-45056'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00308
epssPercentile: 0.21012
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-14T16:14:48.205206Z'
cvssSource: cna
scores:
  cna: 6.9
  vendor: 4.9
ingestedAt: '2026-09-14T11:11:19.877Z'
---

## Overview

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

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45056.json)