CVE-2026-27118
Cache Poisoning in @sveltejs/adapter-vercel Prior to
Publication date: 2026-02-20
Last updated on: 2026-02-20
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| sveltejs | adapter-vercel | to 6.3.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-346 | The product does not properly verify that the source of data or communication is valid. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects versions of @sveltejs/adapter-vercel prior to 6.3.2. It is a cache poisoning issue where an internal query parameter used for Incremental Static Regeneration (ISR) is accessible on all routes. This allows an attacker to manipulate the cache so that sensitive, user-specific responses intended for one user can be served to other users.
To exploit this vulnerability, an attacker needs a victim to visit a specially crafted link while the victim is authenticated. Although existing deployments are protected by Vercel's Web Application Firewall (WAF), users are advised to upgrade to version 6.3.2 to fix the issue.
How can this vulnerability impact me? :
This vulnerability can lead to sensitive user-specific data being cached and then served to other users. This means that private information intended for one user could be exposed to others, potentially leading to data leakage and privacy violations.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade @sveltejs/adapter-vercel to version 6.3.2 or later.
Existing deployments are protected by Vercel's Web Application Firewall (WAF), but upgrading is strongly recommended to fully address the cache poisoning issue.