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    CVE-2026-27121

    svelte performance oriented web framework. Versions of svelte prior to 5.51.5 are vulnerable to cross-site scripting (XSS) during server-side rendering. When using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. This vulnerability is fixed in 5.51.5.

    Published:Feb 20, 2026
    Last Modified:Apr 17, 2026
    EPS:Feb 20, 2026
    EPSS Score:0.00011
    CVSS Score:5.4

    Affected Products

    Vendor
    Svelte
    Product
    Svelte

    Exploits

    No exploit reference

    Related CVEs

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    CVE-2025-15265 (CVSS 5.3) — An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedd…
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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
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    Scope
    Unchanged
    Changed
    Confidentiality
    None
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    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High