CVE-2026-11573 — Uncontrolled recursion in QDomDocument/QDomNode serialization causes stack exhaustion (QtXml)
Uncontrolled recursion (CWE-674) in the QDomDocument/QDomNode serialization path of the Qt XML module (QtXml, qtbase). QDomElementPrivate::save() and QDomNodePrivate::save() recurse mutually, consuming one stack frame per level of element nesting with no depth limit, no configurable bound and no error return. A document with deeply nested elements parses successfully but exhausts the call stack and terminates the process when serialized. Reachable via QDomDocument::toByteArray() (Qt 4.0 and later), QDomDocument::toString(), QDomDocument::toCString(), QDomNode::save(), and operator<<(QTextStream&, const QDomNode&). Denial of service only — no code execution and no memory disclosure.
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 (high)+6
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 (Qt Qt).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- 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 |
|---|---|---|---|---|---|
| 7.1 | CVSS 4.0 | High | — | — | a59d8014-47c4-4630-ab43-e1b13cbe58e3 via NIST National Vulnerability Database |
| 7.1 | CVSS 4.0 | High | — | — | Qt via CVE Program (cve.org) e CISA ADP |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: a59d8014-47c4-4630-ab43-e1b13cbe58e3) 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.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Track CPU/memory spikes and availability drops correlated with request patterns.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · qt/qt
- SSVC assessment updated
- Record published
- CVSS changed · 7.1
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-79680 Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module 21d
- Low CVE-2026-78253 Denial-of-service (stack-exhaustion) vulnerability in QXmlStreamReader::readElementText() impacts Qt 22d
- Low CVE-2026-79616 Out-of-bounds read vulnerability in Context2D.path and PathSvg.path properties impacts Qt Quick 22d
- Medium CVE-2026-76151 Out-of-bounds read (buffer over-read) vulnerability in HTTP Cache-Control response header parsing impacts Qt Framework (QtNetwork module) 29d
- High CVE-2026-19248 Unbounded recursion vulnerability in the QDomNode destructor of Qt XML impacts Qt 29d
- Medium CVE-2026-13326 Out-of-bounds read and integer underflow vulnerability in QNdefNfcTextRecord impacts Qt NFC module Sep 11, 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-2026-11573 is "Uncontrolled recursion in QDomDocument/QDomNode serialization causes stack exhaustion (QtXml)", rated High. It affects Qt (Qt); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 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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