CVE-2025-15265 | THREATINT

Description

An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedded inside a <script> block without HTML‑safe escaping, allowing </script> to terminate the script and inject arbitrary JavaScript. This enables remote script execution in users' browsers, with potential for session theft and account compromise. This issue affects Svelte: from 5.46.0 before 5.46.3.

PUBLISHED Reserved 2025-12-29 | Published 2026-01-15 | Updated 2026-01-15 | Assigner Fluid Attacks

MEDIUM: 5.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Problem types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Product status

Default status

unaffected

5.46.0 (custom) before 5.46.3

affected

Credits

Camilo Vera finder

References

fluidattacks.com/advisories/lydian third-party-advisory

github.com/...svelte/security/advisories/GHSA-6738-r8g5-qwp3 vendor-advisory

fluidattacks.com/advisories/lydian patch

cve.org (CVE-2025-15265)

nvd.nist.gov (CVE-2025-15265)

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