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CVE-2026-43927

MEDIUM
6.9
CVSS 4.0
Description
FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, a race condition in the cart checkout flow allows an authenticated client to apply a promo code beyond its configured maximum uses. By sending concurrent checkout requests before any single request completes the usage increment, a client can obtain unlimited discounted or free orders from a single-use or limited-use promo code. Version 0.8.0 patches the issue. Some workarounds are available. Disable promo codes entirely until a patch is available or monitor the `promo` table for `used` values exceeding `maxuses` and manually review affected orders.

Metadata

CVE ID
CVE-2026-43927
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-05-04 16:59 UTC
Published
2026-07-06 21:49 UTC
Last updated
2026-07-06 21:49 UTC
Primary CWE
CWE-367
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
Vendor / Product
FOSSBilling / FOSSBilling
Sources
cve.org  ·  NVD

Severity & Metrics

6.9 MEDIUM CVSS 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Affected products (1)
VendorProductPlatformVersions
FOSSBilling FOSSBilling — < 0.8.0
Weakness (CWE)
CWESourceDescription
CWE-367 cna CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
CVSS scores (1)
ScoreSeverityVersionSourceVector
6.9 MEDIUM 4.0 cna CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References (1)
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