matrix-react-sdk vulnerable to XSS in Export Chat feature

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N

EPSS

• CVE-2023-37259: 0.45% estimated exploitation activity in the next 30 days; percentile 39.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description The Export Chat feature includes certain attacker-controlled elements in the generated document without sufficient escaping, leading to stored XSS. Impact 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. Patches This was patched in matrix-react-sdk 3.76.0. Workarounds None, other than not using the Export Chat feature. References N/A

Published by the source

18 Jul 2023, 16:58 UTC

Last modified by the source

8 Nov 2023, 04:13 UTC

Source last checked

26 Oct 2026, 12:27 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c9vx-2g7w-rp65

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c9vx-2g7w-rp65

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# Patch Next advisory brief: CVE-2023-37259

Advisory: matrix-react-sdk vulnerable to XSS in Export Chat feature
IDs: CVE-2023-37259, GHSA-c9vx-2g7w-rp65
Record: https://patchnext.com/advisories/cve-2023-37259 (revision 2, source checked 26 Oct 2026, 12:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: matrix-react-sdk 3.76.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm matrix-react-sdk: affected >= 3.32.0, < 3.76.0; fixed in 3.76.0

## Suggested inspection (read-only)
- `npm ls matrix-react-sdk --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on matrix-react-sdk.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-c9vx-2g7w-rp65 (OSV record GHSA-c9vx-2g7w-rp65 lists affected ranges: npm matrix-react-sdk >=3.32.0 <3.76.0 (fixed))
- Verified: https://github.com/advisories/GHSA-c9vx-2g7w-rp65 (GitHub-reviewed advisory GHSA-c9vx-2g7w-rp65 lists affected ranges: npm matrix-react-sdk >=3.32.0 <3.76.0)

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