CVE-2023-37259: Cross site scripting in Export Chat feature

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-18 · updated 2026-06-17
Weakness: CWE-79

Description

matrix-react-sdk is a react-based SDK for inserting a Matrix chat/voip client into a web page. The Export Chat feature includes certain attacker-controlled elements in the generated document without sufficient escaping, leading to stored Cross site scripting (XSS). Since the Export Chat feature generates a separate document, an attacker can only inject code run from the `null` origin, restricting the impact. However, the attacker can still potentially use the XSS to leak message contents. A malicious homeserver is a potential attacker since the affected inputs are controllable server-side. This issue has been addressed in commit `22fcd34c60` which is included in release version 3.76.0. Users are advised to upgrade. The only known workaround for this issue is to disable or to not use the Export Chat feature.

Affected products

matrix-org matrix-react-sdk: from 3.32.0 before 3.76.0; 3.76.0-rc1, 3.76.0-rc2 — fixed in 3.76.0

How to fix

Upgrade to a fixed version: matrix-org matrix-react-sdk 3.76.0. Check the vendor advisory for mitigations.

References

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