# CVE-2026-34573: Parse Server: GraphQL complexity validator exponential fragment traversal DoS

> Unauthenticated attackers can cause denial of service via crafted GraphQL queries in Parse Server deployments with specific complexity validation enabled.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** BIT-parse-2026-34573, GHSA-mfj6-6p54-m98c

## What is CVE-2026-34573?

CVE-2026-34573 is a high-severity denial of service vulnerability in Parseplatform Parse-Server, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.68 and 9.7.0-alpha.12, the GraphQL query complexity validator can be exploited to cause a denial-of-service by sending a crafted query with binary fan-out fragment spreads. A single unauthenticated request can block the Node.js event loop for seconds, denying service to all concurrent users. This only affects deployments that have enabled the requestComplexity.graphQLDepth or requestComplexity.graphQLFields configuration options. This issue has been patched in versions 8.6.68 and 9.7.0-alpha.12.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-34573?

5 open source packages ship an affected version, including parse-server and parse. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `parse-server` | npm | All versions | 8.6.68 |
| `parse-server` | npm | All versions | 8.6.68 |
| `parse-server` | npm | From 9.0.0 | 9.7.0-alpha.12 |
| `parse-server` | npm | From 9.0.0 | 9.7.0-alpha.12 |
| `parse` | Bitnami | All versions | 8.6.68, 9.7.0 |

Products: Parseplatform Parse-Server.

## How do I fix CVE-2026-34573?

Upgrade parse-server to a fixed version for your release line: 8.6.68 or 9.7.0-alpha.12.

## Is CVE-2026-34573 being exploited?

There is no known exploitation of CVE-2026-34573 in the wild and no public exploit code.

## Other vulnerabilities in Parseplatform Parse-Server

- [CVE-2026-30966](https://insights.sbomify.com/CVE-2026-30966/): Parse Server role escalation and CLP bypass via direct `_Join` table write (critical 10.0)
- [CVE-2024-27298](https://insights.sbomify.com/CVE-2024-27298/): Parse Server literalizeRegexPart SQL Injection (critical 10.0)
- [CVE-2022-24760](https://insights.sbomify.com/CVE-2022-24760/): Command Injection in Parse server (critical 10.0)
- [CVE-2026-30965](https://insights.sbomify.com/CVE-2026-30965/): Parse Server session token exfiltration via `redirectClassNameForKey` query parameter (critical 9.9)
- [CVE-2023-36475](https://insights.sbomify.com/CVE-2023-36475/): Parse Server vulnerable to remote code execution via MongoDB BSON parser through prototype pollution (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34573 and fix it if it is affected.

What it is: CVE-2026-34573 is a high-severity denial of service vulnerability in Parseplatform Parse-Server, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34573 in the wild and no public exploit code.

Affected packages and fixed versions:
- parse-server (npm): affected all versions; fixed in 8.6.68
- parse-server (npm): affected all versions; fixed in 8.6.68
- parse-server (npm): affected from 9.0.0; fixed in 9.7.0-alpha.12
- parse-server (npm): affected from 9.0.0; fixed in 9.7.0-alpha.12
- parse (Bitnami): affected all versions; fixed in 8.6.68, 9.7.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34573/ (Markdown: https://insights.sbomify.com/CVE-2026-34573/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34573
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34573
- OSV: https://osv.dev/vulnerability/CVE-2026-34573

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34573/
Summaries are generated and may contain mistakes; the official description above is the record.