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CVE-2026-128122 SvelteKit: Prerendered redirect paths can inject arbitrary rules into the `_redirects` file generated by `@sveltejs/adapter-cloudflare`

5.9 mediumFix available

Medium (5.9) in sveltejs kit. Fixed in @sveltejs/adapter-cloudflare 7.2.10, 8.0.2.

On this page
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 4.7.0 until versions 7.2.10 and 8.0.2, @sveltejs/adapter-cloudflare allowed an attacker-influenced link crawled during prerendering to place whitespace, control characters, wildcards, or placeholders into a prerendered redirect path. The adapter wrote those paths into the Cloudflare _redirects output without output-context validation, allowing a path to create unintended routing rules that could redirect or expose requests beyond the intended prerendered route. This issue is fixed in 7.2.10 and 8.0.2.

Severity

CVSS 3.1

5.9 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CWEs
CWE-79 Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
CWE-93 Improper Neutralization of CRLF Sequences (CRLF Injection)
CWE-116 Improper Encoding or Escaping of Output
OWASP Top 10
A05:2025 Injection
Published
Modified
Assigned by
GitHub_M (CNA)
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
sveltejs kit>= 4.7.0, < 7.2.10
sveltejs kit>= 8.0.0-next.0, < 8.0.2

Fix and patched versions

  • @sveltejs/adapter-cloudflare (npm): fixed in 7.2.10, 8.0.2

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-5wg4-q3ww-283hnpm@sveltejs/adapter-cloudflare>=4.7.0 <7.2.107.2.10
GHSA-5wg4-q3ww-283hnpm@sveltejs/adapter-cloudflare>=8.0.0-next.0 <8.0.28.0.2

Attack patterns (CAPEC)

  • CAPEC-15 Command Delimiters Likelihood: High · Severity: High
  • CAPEC-81 Web Server Logs Tampering Likelihood: Medium · Severity: High
  • CAPEC-73 User-Controlled Filename Likelihood: High · Severity: High
  • CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
  • CAPEC-104 Cross Zone Scripting Likelihood: Medium · Severity: High
  • CAPEC-63 Cross-Site Scripting (XSS) Likelihood: High · Severity: Very High
  • CAPEC-209 XSS Using MIME Type Mismatch Severity: Medium
  • CAPEC-588 DOM-Based XSS Likelihood: High · Severity: Very High
  • CAPEC-591 Reflected XSS Likelihood: High · Severity: Very High
  • CAPEC-592 Stored XSS Likelihood: High · Severity: Very High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

History

  1. The NVD deferred its analysis

Changes since this site first stored the record. The same for every record: /api/public/changes.

References

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