CVE-2026-27118
Cache poisoning in @sveltejs/adapter-vercel
EPSS 0.01%
Description
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.
How to fix CVE-2026-27118
To remediate CVE-2026-27118, upgrade the affected package to a fixed version below.
- —upgrade to 6.3.2 or later
Is CVE-2026-27118 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 6.3.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |