Parse Server LiveQuery subscription with invalid regular expression crashes server

Exploitation

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

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-32770: 0.57% estimated exploitation activity in the next 30 days; percentile 47.31 (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 A remote attacker can crash the Parse Server by subscribing to a LiveQuery with an invalid regular expression pattern. The server process terminates when the invalid pattern reaches the regex engine during subscription matching, causing denial of service for all connected clients. Patches The fix validates regular expression patterns at subscription time, rejecting invalid patterns before they are stored. Additionally, a defense-in-depth try-catch prevents any subscription matching error from crashing the server process. Workarounds Disable LiveQuery if it is not needed.

Published by the source

17 Mar 2026, 18:37 UTC

Last modified by the source

20 Mar 2026, 12:26 UTC

Source last checked

26 Oct 2026, 12:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-827p-g5x5-h86c

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-827p-g5x5-h86c

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# Patch Next advisory brief: CVE-2026-32770

Advisory: Parse Server LiveQuery subscription with invalid regular expression crashes server
IDs: CVE-2026-32770, GHSA-827p-g5x5-h86c
Record: https://patchnext.com/advisories/cve-2026-32770 (revision 2, source checked 26 Oct 2026, 12:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: parse-server 9.6.0-alpha.19, 8.6.43. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm parse-server: affected >= 9.0.0, < 9.6.0-alpha.19; < 8.6.43; fixed in 8.6.43, 9.6.0-alpha.19

## Suggested inspection (read-only)
- `npm ls parse-server --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 parse-server.
- 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-827p-g5x5-h86c (OSV record GHSA-827p-g5x5-h86c lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.43 (fixed))
- Verified: https://github.com/advisories/GHSA-827p-g5x5-h86c (GitHub-reviewed advisory GHSA-827p-g5x5-h86c lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.43)

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