CVE-2026-42573
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 · uneditedSvelte is a performance oriented web framework. Prior to version 5.55.7, Svelte was vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks. This issue has been patched in version 5.55.7.
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 · moderate confidenceSvelte versions prior to 5.55.7 are vulnerable to DOM clobbering, where attackers can manipulate DOM element properties to overwrite Svelte's internal framework state. This manipulation can enable Cross-Site Scripting (XSS) attacks by bypassing the framework's security controls and injecting malicious scripts through the clobbered properties.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 5.55.7CVSS 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
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 checksWork through these to decide whether this CVE applies to you.
-
Locate the Svelte dependency in package.jsonOpen the project root package.json file and locate the 'dependencies' or 'devDependencies' section. Identify the 'svelte' entry and note its version number.Affected if The svelte version listed is less than 5.55.7 (for example, 5.55.6, 5.54.0, 4.x.x, etc.)
-
Verify the installed Svelte version via npmRun the command 'npm list svelte' in the project root directory to display the currently installed Svelte version, including any resolved transitive dependencies.Affected if The displayed version is less than 5.55.7
-
Check the Svelte package directly in node_modulesInspect the file node_modules/svelte/package.json and read the 'version' field to confirm the exact installed version of the Svelte library.Affected if The version field shows a number less than 5.55.7
-
Confirm no patch version is installedIf the version appears to be 5.55.x, verify the exact patch number (the third digit) is 7 or higher. Versions like 5.55.0 through 5.55.6 remain vulnerable.Affected if The installed version is 5.55.0 through 5.55.6 inclusive
If the installed Svelte version is any release prior to 5.55.7, the environment is vulnerable to DOM clobbering and potential XSS.
Generated from the published advisory. Verify against your own configuration.
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 · scoped5.55.7
Upgrade Svelte to version 5.55.7 or later. After upgrading, review existing code for any patterns that may have been exploitable and test for XSS vulnerabilities.
5.55.7
- Update the Svelte version in package.json to "^5.55.7" or "5.55.7"
- Run `npm install` or `yarn install` to fetch the updated package
- Verify the installed version matches 5.55.7 by running `npm list svelte` or `yarn list svelte`
- Rebuild and test the application to ensure the upgrade does not break existing functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42573 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42573 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data