How severe is GHSA-9pq4-5hcf-288c?

No CVSS score has been assigned to GHSA-9pq4-5hcf-288c yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-9pq4-5hcf-288c?

GHSA-9pq4-5hcf-288c affects the following packages: @sveltejs/adapter-vercel (npm). Ecosystems affected: npm.

How do I fix GHSA-9pq4-5hcf-288c?

Update @sveltejs/adapter-vercel to 6.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9pq4-5hcf-288c is resolved across your whole dependency graph.

How do I detect GHSA-9pq4-5hcf-288c in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/adapter-vercel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-9pq4-5hcf-288c if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-9pq4-5hcf-288c?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-9pq4-5hcf-288c can be triaged on real exposure rather than presence alone.

Is GHSA-9pq4-5hcf-288c actively exploited in the wild?

No public exploit code has been indexed for GHSA-9pq4-5hcf-288c yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-9pq4-5hcf-288c?

GHSA-9pq4-5hcf-288c has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 11th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-9pq4-5hcf-288c published, and has it been updated?

GHSA-9pq4-5hcf-288c was published on February 19, 2026 and was last updated on February 23, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

GHSA-9pq4-5hcf-288c — @sveltejs/adapter-vercel

GHSA-9pq4-5hcf-288c is a security vulnerability in @sveltejs/adapter-vercel. A fix is available for @sveltejs/adapter-vercel — see the affected versions and patch details below.

Cache poisoning in @sveltejs/adapter-vercel

Also known asCVE-2026-27118

Published

Feb 19, 2026

Updated

Feb 23, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 24, 2026 · OSV.dev, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-9pq4-5hcf-288c.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs11th percentile — riskier than 11% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

15other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@sveltejs/adapter-vercelnpm

191Kdownloads / week

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@sveltejs/adapter-vercel`	all versions	6.3.2`npm install @sveltejs/adapter-vercel@6.3.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/adapter-vercel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @sveltejs/adapter-vercel to 6.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9pq4-5hcf-288c is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-9pq4-5hcf-288c can be triaged on real exposure rather than presence alone.

Tailored to GHSA-9pq4-5hcf-288c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is GHSA-9pq4-5hcf-288c in your dependencies?

O3 Security finds GHSA-9pq4-5hcf-288c across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works