# CVE-2026-91866: Apache Neethi: Crafted policies cause unbounded work during intersection leading to denial of service

> Attackers can cause denial of service by submitting crafted WS-Policy documents that trigger exponential CPU usage in Apache Neethi.

- **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:** 21 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-q84r-gp7c-vfr3

## What is CVE-2026-91866?

CVE-2026-91866 is a high-severity denial of service vulnerability in Apache Neethi, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A specially crafted pair of WS-Policy documents can force Neethi's policy-intersection to do exponential amounts of work, pinning the CPU for a long time (denial of service).
Users are recommended to upgrade to version 3.2.4, which fixes this issue.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-91866?

It affects 1 product.


Products: Apache Neethi.

## How do I fix CVE-2026-91866?

Upgrade to a fixed version.

## Is CVE-2026-91866 being exploited?

There is no known exploitation of CVE-2026-91866 in the wild and no public exploit code.

## Other vulnerabilities in Apache Neethi

- [CVE-2026-91863](https://insights.sbomify.com/CVE-2026-91863/): Apache Neethi: Uncontrolled recursion while parsing crafted WS-Policy documents allows denial of service (high 7.5)
- [CVE-2026-91864](https://insights.sbomify.com/CVE-2026-91864/): Apache Neethi: Crafted WS-Policy documents bypass element/attribute limits causing memory exhaustion (high 7.5)
- [CVE-2026-91865](https://insights.sbomify.com/CVE-2026-91865/): Apache Neethi: Crafted policy references cause exponential expansion during normalization leading to denial of service (high 7.5)
- [CVE-2026-66142](https://insights.sbomify.com/CVE-2026-66142/): Apache Neethi: Uncontrolled recursion in policy processing (high 7.5)
- [CVE-2026-66143](https://insights.sbomify.com/CVE-2026-66143/): Apache Neethi: Missing global alternative-output budget across policy computation paths (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91866 and fix it if it is affected.

What it is: CVE-2026-91866 is a high-severity denial of service vulnerability in Apache Neethi, published on 21 Sep 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-2026-91866 in the wild and no public exploit code.

Affected product: Apache Neethi. 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-2026-91866/ (Markdown: https://insights.sbomify.com/CVE-2026-91866/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91866
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91866
- OSV: https://osv.dev/vulnerability/CVE-2026-91866

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91866/
Summaries are generated and may contain mistakes; the official description above is the record.