Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.39% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-11573High confidence
Uncontrolled recursion in QDomDocument/QDomNode serialization causes stack exhaustion (QtXml)
qt · qt
7.1HighCVSS 4.0
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 16 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs qt qt and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 16 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 11 affected or under-investigation product states without a fixed product state in the same current advisory
- Debian Security Tracker: 5 affected package states with no published fix
Distribution package intelligence
10 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 5 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | qt6-base | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.8.2+dfsg-5 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian trixietrixie · source | qtbase-opensource-src | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | qt6-base | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | qtbase-opensource-src | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | qt6-base | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.8.2+dfsg-5 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | qtbase-opensource-src | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | qt6-base | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.8.2+dfsg-5 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | qtbase-opensource-src | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · esm-apps | qtbase-opensource-src | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | qt6-base | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2026-11573 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityqtbase: qt5-qtbase: qt6-qtbase: qtbase: Denial of Service via uncontrolled recursion in XML serialization
The vendor explicitly identifies these products as affected by this CVE.
- qt6-qtbase as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-common as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-devel as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-examples as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-gui as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-mysql as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-odbc as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-postgresql as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-private-devel as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-static as a component of Red Hat Enterprise Linux 10
- qt6-qtbase.src as a component of Red Hat Enterprise Linux 10
- Summary
- A flaw was found in qtbase. Uncontrolled recursion in Qt's QDomDocument serialization (QtXml) allows a remote attacker to provide deeply nested untrusted XML, leading to stack exhaustion. This can cause the application to crash, resulting in a Denial of Service (DoS).
- Remediation
- To mitigate this issue, applications that use Qt's QDomDocument for XML serialization should avoid processing untrusted XML input. If processing untrusted XML is unavoidable, implement robust input validation and sanitization to prevent deeply nested structures before passing the data to the QtXml component. This requires application-level changes or careful operational procedures to ensure only trusted XML is processed.
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 16 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
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.
What
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.
Why
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
What
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.
Why
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Uncontrolled Recursion → disrupt the affected service
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Passive interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Not a CVSS 4.0 base metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-674 ↗
CWE-674: Uncontrolled Recursion. The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCommon Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIPassiveUser interaction: A user must unknowingly interact with the vulnerable system.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Affected
- qt6-qtbase as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-common as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-devel as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-examples as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-gui as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-mysql as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-odbc as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-postgresql as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-private-devel as a component of Red Hat Enterprise Linux 10
- qt6-qtbase-static as a component of Red Hat Enterprise Linux 10
- qt6-qtbase.src as a component of Red Hat Enterprise Linux 10
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- To mitigate this issue, applications that use Qt's QDomDocument for XML serialization should avoid processing untrusted XML input. If processing untrusted XML is unavoidable, implement robust input validation and sanitization to prevent deeply nested structures before passing the data to the QtXml component. This requires application-level changes or careful operational procedures to ensure only trusted XML is processed.
04
Evidence and provenance
Published 8 Sept 2026 · Last source change 11 Sept 2026, 09:31 UTC · CWE-674 · Uncontrolled Recursion
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-09-09
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-72717
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- 6.7.0 < 6.8.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- 2.2.0 < 6.8.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- ENISA EUVD mappingEUVD-2026-72717 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-72717"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.