CVE-2026-71537

Paymenter: Credit-refund double-spend race condition in service downgrade (doUpgrade)

MEDIUM
6.5
CVSS Score
Published: September 18, 2026 at 05:43 PM UTC
Updated: September 24, 2026 at 09:18 PM UTC
1 product affected across 1 vendorPaymenter

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Paymenter is a free and open-source webshop solution for management of hosting services. Prior to 1.5.7, app/Livewire/Services/Upgrade.php::doUpgrade() relies on Service::upgradable to check for a pending service upgrade and later executes $credit->increment('amount', abs($price)) without DB::transaction or lockForUpdate() spanning those operations. An authenticated customer with an active downgradable service can submit concurrent downgrade requests that each observe no pending upgrade, create separate upgrade records, and increment the same account credit balance, producing multiple spendable refunds for one downgrade. This issue is fixed in version 1.5.7.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.5.7
Affected range stops below 1.5.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-362

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