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

> An unauthenticated attacker can crash the UPnP service by sending deeply nested XML, causing a stack overflow in recursive DOM functions.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-55862, GHSA-25cx-xv8x-j247, UBUNTU-CVE-2026-55862

## What is CVE-2026-55862?

CVE-2026-55862 is a medium-severity denial of service vulnerability in pupnp, published on 16 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-55862?

It affects 1 product.


Products: Pupnp Project Pupnp.

## How do I fix CVE-2026-55862?

Upgrade to a fixed version.

## Is CVE-2026-55862 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55862 exists.

## Other vulnerabilities in pupnp

- [CVE-2021-29462](https://insights.sbomify.com/CVE-2021-29462/): DNS rebinding in pupnp (high 7.6)
- [CVE-2026-57486](https://insights.sbomify.com/CVE-2026-57486/): pupnp: NULL pointer dereference in ixmlNode_compare crashes on non-namespaced attributes (high 7.5)
- [CVE-2026-57487](https://insights.sbomify.com/CVE-2026-57487/): libupnp chunked HTTP bodies can bypass g_maxContentLength and be fully buffered (high 7.5)
- [CVE-2026-77630](https://insights.sbomify.com/CVE-2026-77630/): pupnp: Denial of service via blocking DNS resolution in parse_uri()/GENA callback parsing (high 7.5)
- [CVE-2021-28302](https://insights.sbomify.com/CVE-2021-28302/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55862 and fix it if it is affected.

What it is: CVE-2026-55862 is a medium-severity denial of service vulnerability in pupnp, published on 16 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55862 exists.

Affected product: pupnp. 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-2026-55862/ (Markdown: https://insights.sbomify.com/CVE-2026-55862/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55862
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55862
- OSV: https://osv.dev/vulnerability/CVE-2026-55862

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55862/
Summaries are generated and may contain mistakes; the official description above is the record.