CVE-2026-42599: medium-severity vulnerability in sveltejs svelte
Cross-site scripting via spread attributes in Svelte SSR
Published
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.1epss 0.2%
Svelte is a performance oriented web framework. Prior to version 5.55.7, 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. Note that this vulnerability only triggers if the user's browser has JavaScript enabled but Svelte's hydration mechanism does not reach the vulnerable element before the event fires. This issue has been patched in version 5.55.7.
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
Affected products
sveltejs · svelteRelated CVEs — sveltejs svelte
In the same product, most dangerous first.
CVE-2026-42567MEDIUMSvelte: ReDoS in `<svelte:element>` Tag ValidationEPSS 0.5%CVE-2026-27125MEDIUMSvelte SSR attribute spreading includes inherited properties from prototype chainEPSS 0.4%CVE-2024-45047MEDIUMPotential mXSS vulnerability due to improper HTML escaping in svelteEPSS 0.4%CVE-2026-42573MEDIUMSvelte: XSS via DOM Clobbering of Internal Framework StateEPSS 0.3%CVE-2026-27902MEDIUMSvelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration MarkersEPSS 0.3%CVE-2026-27901MEDIUMSvelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent`EPSS 0.3%