XSS in Matrix-Org Matrix-React-Sdk

CVE-2023-37259

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (36.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-37259: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-37259?
CVE-2023-37259 is a medium-severity vulnerability in Matrix-Org Matrix-React-Sdk, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-07-18.
How severe is CVE-2023-37259?
Medium severity. CVSS v3 base score is 6.1 out of 10.