CVE-2026-55862 — pupnp: Incomplete fix for CVE-2021-28302: recursive DOM functions cause stack overflow
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Pupnp Pupnp).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 6.5 | CVSS 3.1 | Medium | 2.8 | 3.6 | security-advisories@github.com via NIST National Vulnerability Database |
| 6.5 | CVSS 3.1 | Medium | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Track CPU/memory spikes and availability drops correlated with request patterns.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Source status changed · Published → Awaiting Analysis
- Record published
- CVSS changed · 6.5
- Source status changed · → Published
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 16, 2026 – Oct 16, 2026
References
3 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-77630 pupnp: Denial of service via blocking DNS resolution in parse_uri()/GENA callback parsing 17h
- High CVE-2026-57486 pupnp: NULL pointer dereference in ixmlNode_compare crashes on non-namespaced attributes 17h
- High CVE-2026-57487 libupnp chunked HTTP bodies can bypass g_maxContentLength and be fully buffered 17h
- High CVE-2026-57488 pupnp: Integer truncation in HTTP Content-Length parsing enables request smuggling 17h
- Medium CVE-2026-41682 pupnp: Port truncation via atoi() cast in parse_uri() allows SSRF port confusion May 8, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-55862 is "pupnp: Incomplete fix for CVE-2021-28302: recursive DOM functions cause stack overflow", rated Medium. It affects Pupnp (Pupnp); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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