Paymenter: Credit-refund double-spend race condition in service downgrade (doUpgrade) (CVE-2026-71537) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-71537GHSA-5GMM-HJFJ-8FF7

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

Answer in brief

CVE-2026-71537 records a Medium severity (CVSS 6.5) vulnerability in Paymenter: Credit-refund double-spend race condition in service downgrade (doUpgrade). The current sources do not mark it as known exploited. The current feed maps paymenter/paymenter (composer), Paymenter/Paymenter (generic), paymenter/paymenter (packagist). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 18, 2026Updated Sep 18, 2026Source checked Sep 18, 2026First seen by HOL Sep 18, 2026Material review Sep 18, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps paymenter/paymenter (composer), Paymenter/Paymenter (generic), paymenter/paymenter (packagist). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
paymenter/paymentercomposer	<=1.5.6	1.5.7
Paymenter/Paymentergeneric	< 1.5.7	Not reported
paymenter/paymenterpackagist	>=0 <1.5.7	1.5.7

Recommended response

Check inventory. Check lockfiles and deployed manifests for paymenter/paymenter, Paymenter/Paymenter, paymenter/paymenter.
Review the reported fix. Update paymenter/paymenter to 1.5.7; paymenter/paymenter to 1.5.7 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 18, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.