dbcve.org
Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-6210

HIGH · 8.7 CVSS v4.0 Published 2026-05-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
96/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A type confusion vulnerability in Qt SVG allows an attacker to cause an application crash via a crafted SVG image. When processing SVG marker references, the renderer retrieves a node by its id attribute and casts it to QSvgMarker* without verifying the node type. A non-marker element (such as a <line> element) that references itself as a marker triggers an out-of-bounds heap read due to the object size difference between QSvgLine and QSvgMarker, followed by an endless recursion that bypasses the marker recursion guard through incorrect virtual dispatch. The result is an application crash (denial of service). This issue affects Qt SVG:  from 6.7.0 before 6.8.8, from 6.9.0 before 6.11.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A type confusion vulnerability in Qt SVG allows attackers to crash applications via crafted SVG images. The renderer casts nodes to QSvgMarker* without type verification, and when a non-marker element (e.g., <line>) references itself as a marker, it triggers an out-of-bounds heap read due to object size differences between QSvgLine and QSvgMarker, followed by recursion that bypasses the marker recursion guard through incorrect virtual dispatch.

MitigationUpdate Qt SVG to version 6.8.8, 6.11.1, or later to patch the type confusion and recursion bypass issues. Until patched, avoid processing untrusted SVG files with vulnerable Qt applications.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Qt installation and version
    Run 'qmake --version' or check Qt binaries/libraries in system paths (e.g., /usr/lib/x86_64-linux-gnu/libQt6Svg.so on Linux, or inspect Qt6Core.dll properties on Windows). Also check your application's linked Qt libraries using 'ldd <application>' or dependency walker tools.
    Affected if Qt version is found and is below 6.8.8 or 6.11.1 (the fixed releases)
  2. Confirm QtSvg module is loaded
    Inspect your application's dependencies or runtime loaded modules to verify QtSvg (Qt6Svg or Qt5Svg) is present. On Linux: 'ldd <app> | grep -i svg'. On Windows: check for Qt6Svg.dll or Qt5Svg.dll in process modules.
    Affected if QtSvg module is linked or loaded into the application
  3. Determine if SVG processing is active
    Review application code or configuration for use of QSvgRenderer, QSvgWidget, or QImage loading SVG files. Check for file type handling that accepts .svg input, or network/data ingestion that processes SVG content.
    Affected if Application parses or renders SVG files from any source
  4. Check for untrusted SVG input handling
    Audit whether the application processes SVG files from external or untrusted sources (user uploads, network requests, file system locations controlled by other users, or data parsing routines that may contain SVG).
    Affected if Application handles SVG input from untrusted sources without sanitization

You are affected if your Qt installation uses the QtSvg module, processes SVG files (especially from untrusted sources), and the Qt version is below 6.8.8 or 6.11.1.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Qt SVG to version 6.8.8, 6.11.1, or later to patch the type confusion and recursion bypass issues. Until patched, avoid processing untrusted SVG files with vulnerable Qt applications.

Recommended fix High confidence

Qt 6.8.8 or Qt 6.11.1 (depending on which release branch you are on)

  1. 1. Identify the current Qt SVG version in use by checking your project's Qt installation or dependencies.
  2. 2. If using Qt 6.7.x: upgrade to Qt 6.8.8 or later.
  3. 3. If using Qt 6.8.x (versions before 6.8.8): upgrade to Qt 6.8.8 or later.
  4. 4. If using Qt 6.9.x, 6.10.x, or 6.11.0: upgrade to Qt 6.11.1 or later.
  5. 5. Rebuild and redeploy the application with the updated Qt libraries.
  6. 6. Test the application with SVG rendering functionality to verify the fix works correctly.
Caveat Minor - Qt maintains backward compatibility within major versions, but always test your application after upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,880
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-6210 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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