CVE-2026-34748: @payloadcms/next Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-mmxc-95ch-2j7c
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CVSS 8.7
CWE-79
Published
Advisory Summary

CVE-2026-34748 is a HIGH (CVSS 8.7) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting @payloadcms/next libraries in the npm ecosystem. The issue involves @payloadcms/next has stored xss in admin panel. Remediation is available by upgrading affected packages to version 3.78.0.

CVE-2026-34748 at a Glance

CVE Identifier CVE-2026-34748
GHSA Identifier GHSA-mmxc-95ch-2j7c
Severity HIGH
CVSS v3.1 Base Score 8.7
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product @payloadcms/next
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 8.7

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-34748

To remediate this vulnerability, upgrade all affected @payloadcms/next dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@payloadcms/next fixed: 3.78.0 
npm install @payloadcms/next@3.78.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @payloadcms/next

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-34748, inspect your project dependencies using npm:

npm ls @payloadcms/next

Analyze the terminal output to locate any version of @payloadcms/next in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.78.0), your application is affected.

Note: The npm ls @payloadcms/next command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In @payloadcms/next, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact A stored Cross-site Scripting (XSS) vulnerability existed in the admin panel. An authenticated user with write access to a collection could save content that, when viewed by another user, would execute in their browser. Consumers are affected if ALL of these are true: - Payload version **< v3.78.0** - At least one collection with versions enabled - An authenticated user has `create` or `update` access to that collection ### Patches This vulnerability has been patched in **v3.78.0**. Output encoding has been added to prevent user-supplied content from being interpreted as markup. Users should upgrade to **v3.78.0** or later. ### Workarounds If consumers cannot upgrade immediately: - Restrict `create` and `update` access to versioned collections to trusted roles only.

CVE-2026-34748 Affected @payloadcms/next Versions

1 component(s)
Fixed Versions:
3.78.0
Product / Package Ecosystem Affected Versions Fixed Version
@payloadcms/next
npm/@payloadcms/next
npm
< 3.78.0
3.78.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/payloadcms/payload/security/advisories/GHSA-mmxc-95ch-2j7c
NVD — CVE-2026-34748 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34748
@payloadcms/next Source Repository REPOSITORY
https://github.com/payloadcms/payload

Frequently Asked Questions

What is CVE-2026-34748?
CVE-2026-34748 is a security vulnerability in @payloadcms/next involving @payloadcms/next has Stored XSS in Admin Panel under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which @payloadcms/next versions are affected?
Affected versions include releases prior to 3.78.0 across affected packages: @payloadcms/next.
What version fixes CVE-2026-34748?
Upgrading to 3.78.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @payloadcms/next affected?
Yes, @payloadcms/next is affected in releases prior to 3.78.0. Upgrade your dependency to 3.78.0 or later.
What is the CVSS score of CVE-2026-34748?
CVE-2026-34748 has a CVSS v3.1 base score of 8.7 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.
What CWE is associated with CVE-2026-34748?
CVE-2026-34748 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check npm dependencies for CVE-2026-34748?
Run the dependency tree command: 'npm ls @payloadcms/next'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mmxc-95ch-2j7c",
  "modified" : "2026-04-06T16:46:57Z",
  "published" : "2026-04-01T21:24:22Z",
  "aliases" : [ "CVE-2026-34748" ],
  "summary" : "@payloadcms/next has Stored XSS in Admin Panel",
  "details" : "### Impact\n\nA stored Cross-site Scripting (XSS) vulnerability existed in the admin panel. An authenticated user with write access to a collection could save content that, when viewed by another user, would execute in their browser.\n\nConsumers are affected if ALL of these are true:\n\n- Payload version **< v3.78.0**\n- At least one collection with versions enabled\n- An authenticated user has `create` or `update` access to that collection\n\n### Patches\n\nThis vulnerability has been patched in **v3.78.0**. Output encoding has been added to prevent user-supplied content from being interpreted as markup.\n\nUsers should upgrade to **v3.78.0** or later.\n\n### Workarounds\n\nIf consumers cannot upgrade immediately:\n\n- Restrict `create` and `update` access to versioned collections to trusted roles only.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@payloadcms/next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.78.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/payloadcms/payload/security/advisories/GHSA-mmxc-95ch-2j7c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34748"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/payloadcms/payload"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T21:24:22Z",
    "nvd_published_at" : "2026-04-01T20:16:27Z"
  }
}