OpenMage magento-lts before 20.19.0 Race Condition in Coupon Usage Limits
CVE-2026-128042

6.3MEDIUM

Key Information:

Vendor

Openmage

Status
Magento-lts
Vendor
CVE Published:
13 November 2026

What is CVE-2026-128042?

OpenMage magento-lts before 20.19.0 and 21.0.0-beta1 before 21.0.0-beta3 contains a race condition in shopping cart price rule usage limits, because Mage_SalesRule_Model_Validator checks coupon limits without locking and the usage counters are later incremented non-atomically. Unauthenticated attackers, including guest shoppers, can submit concurrent checkouts to redeem a limited coupon more times than its cap allows.

Affected Version(s)

magento-lts 0 < 20.19.0

magento-lts 21.0.0-beta1 < 21.0.0-beta3

magento-lts 20.19.0

References

https://github.com/OpenMage/magento-lts/security/advisori...
vendor-advisory
https://github.com/OpenMage/magento-lts/commit/2626f027a7...
patch
https://www.vulncheck.com/advisories/openmage-magento-lts...
third-party-advisory

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

skeletonsec
colinmollenhour
.