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Payload: Remote Code Execution through first-register

High severity GitHub Reviewed Published Sep 18, 2026 in payloadcms/payload • Updated Oct 7, 2026

Package

npm payload (npm)

Affected versions

< 3.90.0
>= 4.0.0-canary.0, < 4.0.0-canary.34

Patched versions

3.90.0
4.0.0-canary.34

Description

Impact

A crafted request to the public first-register operation can be used to perform a RCE exploit.

You are affected if:

  • You use local auth strategy and your application remains without an initial user created

Patches

In the patched version data submission to create first user is properly sanitized.

Users should upgrade Payload packages to >= 3.90.0 or >= 4.0.0-canary.34.

References

@DanRibbens DanRibbens published to payloadcms/payload Sep 18, 2026
Published by the National Vulnerability Database Oct 6, 2026
Published to the GitHub Advisory Database Oct 7, 2026
Reviewed Oct 7, 2026
Last updated Oct 7, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(41st percentile)

Weaknesses

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Learn more on MITRE.

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. Learn more on MITRE.

CVE ID

CVE-2026-105858

GHSA ID

GHSA-97rh-rhh2-7vjv

Source code

Credits

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