VulnerabilityDeferred

CVE-2026-27118

Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning.

MEDIUM 5.3EPSS 0.26%

Does this matter?

Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own.

Description

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. 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. This vulnerability is fixed in 6.3.2.

CVSS 4.0: 5.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.26% probability · 18th percentile
CISA KEV: Not listed
Weakness: CWE-346
Source: security-advisories@github.com

References

https://github.com/sveltejs/kit/security/advisories/GHSA-9pq4-5hcf-288c

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.