mercurius has Uncaught Exception when using subscriptions

Exploitation

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

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2023-22477: 1.09% estimated exploitation activity in the next 30 days; percentile 65.33 (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.

Impact Any users of Mercurius until version v11.5.0 are subjected to a denial of service attack by sending a malformed packet over WebSocket to /graphql. Patches This was patched in https://github.com/mercurius-js/mercurius/pull/940. The patch was released as v11.5.0 and v8.13.2. Workarounds Disable subscriptions. References Reported publicly as https://github.com/mercurius-js/mercurius/issues/939. The same problem was solved in https://github.com/fastify/fastify-websocket/pull/228

Published by the source

9 Jan 2023, 21:55 UTC

Last modified by the source

8 Nov 2023, 04:11 UTC

Source last checked

26 Oct 2026, 12:21 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cm8h-q92v-xcfc

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-cm8h-q92v-xcfc

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# Patch Next advisory brief: CVE-2023-22477

Advisory: mercurius has Uncaught Exception when using subscriptions
IDs: CVE-2023-22477, GHSA-cm8h-q92v-xcfc
Record: https://patchnext.com/advisories/cve-2023-22477 (revision 2, source checked 26 Oct 2026, 12:21 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mercurius 11.5.0, 8.13.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mercurius: affected >= 9.0.0, < 11.5.0; < 8.13.2; fixed in 8.13.2, 11.5.0

## Suggested inspection (read-only)
- `npm ls mercurius --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 mercurius.
- 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-cm8h-q92v-xcfc (OSV record GHSA-cm8h-q92v-xcfc lists affected ranges: npm mercurius >=9.0.0 =0 <8.13.2 (fixed))
- Verified: https://github.com/advisories/GHSA-cm8h-q92v-xcfc (GitHub-reviewed advisory GHSA-cm8h-q92v-xcfc lists affected ranges: npm mercurius >=9.0.0 =0 <8.13.2)

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