How severe is CVE-2024-53261?

No CVSS score has been assigned to CVE-2024-53261 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-53261?

CVE-2024-53261 affects the following packages: @sveltejs/kit (npm). Ecosystems affected: npm.

How do I fix CVE-2024-53261?

Update @sveltejs/kit to 2.8.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-53261 is resolved across your whole dependency graph.

How do I detect CVE-2024-53261 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-53261 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2024-53261 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-53261 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-53261?

CVE-2024-53261 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 29th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-53261?

CVE-2024-53261 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2024-53261 published, and has it been updated?

CVE-2024-53261 was published on November 25, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2024-53261 — @sveltejs/kit

Fix: sveltejs/kit@d338d46

CVE-2024-53261 is a Cross-site Scripting (XSS) vulnerability in @sveltejs/kit. A fix is available for @sveltejs/kit — see the affected versions and patch details below.

Cross-Site Scripting attack (XSS) on dev mode 404 page in SvelteKit

Also known asGHSA-rjjv-87mx-6x3h

Published

Nov 25, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-53261.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk+0.02%

Lower risk than most CVEs29th percentile — riskier than 29% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

216other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@sveltejs/kitnpm

5.0Mdownloads / week

Description

Summary

"Unsanitized input from the request URL flows into end, where it is used to render an HTML page returned to the user. This may result in a Cross-Site Scripting attack (XSS)."

Details

Source of potentially tainted data is in packages/kit/src/exports/vite/dev/index.js, line 437. This potentially tainted data is passed through a number of steps (which I could detail if you'd like) all the way down to line 91 in packages/kit/src/exports/vite/utils.js, which performs an operation that Snyk believes an attacker shouldn't be allowed to manipulate.

Another source of potentially tainted data (according to Snyk) comes from ‎packages/kit/src/exports/vite/utils.js, line 30, col 30 (i.e., the url property of req). This potentially tainted data is passed through a number of steps (which I could detail if you'd like) all the way down line 91 in packages/kit/src/exports/vite/utils.js, which performs an operation that Snyk believes an attacker shouldn't be allowed to manipulate.

PoC

Not provided

Impact

Little to none. The Vite development is not exposed to the network by default. And even if someone were able to trick a developer into executing an XSS against themselves, a development database should not have any sensitive data.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@sveltejs/kit`	all versions	2.8.3`npm install @sveltejs/kit@2.8.3`

Affected Products

1 product · 1 configurations

Application

sveltekitsvelte

< 2.8.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @sveltejs/kit to 2.8.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-53261 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Summary "Unsanitized input from *the request URL* flows into `end`, where it is used to render an HTML page returned to the user. This may result in a Cross-Site Scripting attack (XSS)." ### Details Source of potentially tainted data is in `packages/kit/src/exports/vite/dev/index.js`, line 437. This potentially tainted data is passed through a number of steps (which I could detail if you'd like) all the way down to line 91 in `packages/kit/src/exports/vite/utils.js`, which performs an operation that Snyk believes an attacker shouldn't be allowed to manipulate. Another source of potenti

O3 Security · Impact-Aware SCA

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