# CVE-2026-9563: Denial of service in Eclipse Parsson

> Attackers can cause denial of service in applications using Eclipse Parsson by submitting large JSON documents that exhaust CPU and memory resources.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Jul 2026
- **Updated:** 2 Jul 2026
- **Also known as:** CLEANSTART-2026-IC85563, CLEANSTART-2026-WV26329, CLEANSTART-2026-XT77636, ECHO-058e-4aa6-dafa, GHSA-q86x-4w7f-8hrm

## What is CVE-2026-9563?

CVE-2026-9563 is a high-severity denial of service vulnerability in Eclipse Parsson, published on 2 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Parsson published Maven Central artifacts before version 1.1.8, the JSON parser did not enforce a default maximum on the number of characters consumed while parsing a single JSON document. Applications that parse attacker- controlled JSON can be forced to consume excessive CPU and memory by processing very large documents, including large arrays, objects, strings, numbers, whitespace, or nested structures, resulting in a denial of service. Eclipse Parsson 1.1.8 introduces a configurable maximum parsing limit with a default limit of 15 million parser-consumed characters.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-9563?


## How do I fix CVE-2026-9563?

Upgrade to a fixed version.

## Is CVE-2026-9563 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9563 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9563 and fix it if it is affected.

What it is: CVE-2026-9563 is a high-severity denial of service vulnerability in Eclipse Parsson, published on 2 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9563 exists.

Affected product: Eclipse Parsson. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-9563/ (Markdown: https://insights.sbomify.com/CVE-2026-9563/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9563
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9563
- OSV: https://osv.dev/vulnerability/CVE-2026-9563

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9563/
Summaries are generated and may contain mistakes; the official description above is the record.