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

Quick assessment

Affected
Paymenter Paymenter
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Paymenter 是一个免费且开源的 Web 商店解决方案，用于管理托管服务。在 1.5.7 版本之前， 中的 方法依赖于 来检查是否存在待处理的服务升级，随后执行 ，但整个过程并未使用 或 将“检查待处理升级”与“增加信用额度”这两个操作包裹在同一事务中。 在这种情况下，一个拥有活跃且可降级服务的已认证客户，可以并发提交多个降级请求。由于缺乏适当的并发控制，每个请求在检查时都可能观察到“没有待处理的升级”，从而各自创建独立的升级记录，并多次对同一账户的信用额度余额进行累加操作。这会导致一次降级产生多笔可使用的退

CVSS 6.5 · Medium EPSS 0.23% · P14

Possible ATT&CK Techniques 1 AI

T1490 · Inhibit System Recovery

Affected Version Matrix 1

VendorProduct Version RangeStatus
Paymenter Paymenter < 1.5.7 affected
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I. Basic Information for CVE-2026-71537

Vulnerability Information
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Vulnerability Title
Paymenter: Credit-refund double-spend race condition in service downgrade (doUpgrade)
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
使用共享资源的并发执行不恰当同步问题(竞争条件)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Paymenter Paymenter < 1.5.7 -

II. Public POCs for CVE-2026-71537

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III. Intelligence Information for CVE-2026-71537

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Patches & Fixes for CVE-2026-71537 (1)

Other References for CVE-2026-71537 (2)

IV. Related Vulnerabilities

Same product: Paymenter
Same vendor: Paymenter
Same weakness: CWE-362

V. Comments for CVE-2026-71537

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