Cache poisoning in @sveltejs/adapter-vercel
Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users.
Successful exploitation requires a victim to visit an attacker-controlled link while authenticated.
Existing deployments are protected by Vercel's WAF, but users should upgrade as soon as possible.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @sveltejs/adapter-vercel | < 6.3.2 | 6.3.2 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-346- Platform
- npm
- Package
@sveltejs/adapter-vercel- Disclosed
- 19.02.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-9pq4-5hcf-288c - CC BY 4.0
Vulnerability history: @sveltejs/adapter-vercel
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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