User content sandbox can be confused into opening arbitrary documents
Impact
The user content sandbox can be abused to trick users into opening unexpected documents after several user interactions. The content can be opened with a blob origin from the Matrix client, so it is possible for a malicious document to access user messages and secrets.
Patches
This has been fixed by https://github.com/matrix-org/matrix-react-sdk/pull/5657, which is included in 3.15.0.
Workarounds
There are no known workarounds.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | matrix-react-sdk | < 3.15.0 | 3.15.0 |
References
- https://github.com/matrix-org/matrix-react-sdk/security/advisories/GHSA-52mq-6jcv-j79x
- https://nvd.nist.gov/vuln/detail/CVE-2021-21320
- https://github.com/matrix-org/matrix-react-sdk/pull/5657
- https://github.com/matrix-org/matrix-react-sdk/commit/b386f0c73b95ecbb6ea7f8f79c6ff5171a8dedd1
- https://www.npmjs.com/package/matrix-react-sdk
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N- Weakness (CWE)
CWE-345- Platform
- npm
- Package
matrix-react-sdk- Disclosed
- 03.03.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-52mq-6jcv-j79x - CC BY 4.0
Vulnerability history: matrix-react-sdk
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 03.2021 10.2024
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 3
- Low 1
Disclosures per year
- 2021: 2
- 2022: 0
- 2023: 4
- 2024: 2
- 2025: 0
- 2026: 0
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User content sandbox can be confused into opening arbitrary documents this entry
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