CVE
kit server secret disclosure in build-time import guard
Affects SvelteKit (@sveltejs/kit) 3.0.0 through 3.1.0 when server-only imports go through src/params.js. Fixed in 3.1.1.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 3.1.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.1.1.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
SvelteKit, a web application framework, has a build-time guard that failed to treat src/params.js as client-side code, so server-only modules imported through it could end up in the browser bundle. An attacker can remotely, without logging in, read server secrets such as private environment values that were exposed there.
Read the original description
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 3.0.0 until 3.1.1, the build-time server-only module guard did not treat src/params.js as a client entry point even though parameter matchers can run in the browser. Server-only modules imported through src/params.js could consequently enter the client bundle, where statically replaced private environment values or other server secrets could be exposed. This issue is fixed in 3.1.1.
Who should check
Teams running SvelteKit 3.0.0 through 3.1.0 that import server-only modules through src/params.js, such as $app/env/private or *.server.js files.
Read the source excerpt
“This could only occur when those server-only imports were made through src/params.js”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 70 if added to CISA KEV
- Would score about 65 if CISA's SSVC rates exploitation active
- Would score about 30 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.1.1.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-128118 (SvelteKit: Build-time server-only module import guard could fail, resulting in server secrets being statically replaced in client bundle), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-128118 (entry last updated 2026-11-13):
Affected:
- sveltejs kit: from 3.0.0, fixed in 3.1.1
Fixed versions: 3.1.1.
Conditions (all must be true for the bug to be hit):
- SvelteKit (@sveltejs/kit) versions 3.0.0 through 3.1.0 (source: https://github.com/sveltejs/kit/security/advisories/GHSA-m9j8-jcmv-hp69)
- Server-only imports must be made through src/params.js (source: https://github.com/sveltejs/kit/security/advisories/GHSA-m9j8-jcmv-hp69)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-128118 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128118 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/sveltejs/kit/security/advisories/GHSA-m9j8-jcmv-hp69
- https://github.com/sveltejs/kit/commit/ae07803806f75b8b5662ae4ab92934ca1356fd84
- https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@3.1.1
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-128118
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-128118"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- sveltejs kit
From 3.0.0 · fixed in 3.1.1
Evidence 5
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 2
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-128118
Is CVE-2026-128118 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A build-time guard that keeps server-only modules out of client code could fail. When it does, server-only code can enter the client bundle, potentially exposing secrets such as server environment values.Source: github.com
Which versions are affected by CVE-2026-128118?
kit: from 3.0.0 before 3.1.1.Source: cve.now feed data
Am I affected, and how do I check?
Versions 3.0.0 through 3.1.0 of @sveltejs/kit are in scope, and only when server-only imports are made through src/params.js. To check, look at the @sveltejs/kit version in the project's package.json or lockfile, and whether src/params.js imports server-only modules.Source: github.com
How do I fix CVE-2026-128118?
Upgrade @sveltejs/kit to 3.1.1, the fixed version, or later.Source: github.com