CVE-2026-31824

CVE-2026-31824 is a high-severity vulnerability in Sylius with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-367.

Key facts

Description

Sylius is an Open Source eCommerce Framework on Symfony. A Time-of-Check To Time-of-Use (TOCTOU) race condition was discovered in the promotion usage limit enforcement. The same class of vulnerability affects the promotion usage limit (the global used counter on Promotion entities), coupon usage limit (the global used counter on PromotionCoupon entities), and coupon per-customer usage limit (the per-customer redemption count on PromotionCoupon entities). In all three cases, the eligibility check reads the used counter (or order count) from an in-memory Doctrine entity during validation, while the actual usage increment in OrderPromotionsUsageModifier happens later during order completion — with no database-level locking or atomic operations between the two phases. Because Doctrine flushes an absolute value (SET used = 1) rather than an atomic increment (SET used = used + 1), and because the affected entities lack optimistic locking, concurrent requests all read the same stale usage counts and pass the eligibility checks simultaneously. An attacker can exploit this by preparing multiple carts with the same limited-use promotion or coupon and firing simultaneous PATCH /api/v2/shop/orders/{token}/complete requests. All requests pass the usage limit checks and complete successfully, allowing a single-use promotion or coupon to be redeemed an arbitrary number of times. The per-customer limit can be bypassed in the same way by a single customer completing multiple orders concurrently. No authentication is required to exploit this vulnerability. This may lead to direct financial loss through unlimited redemption of limited-use promotions and discount coupons. The issue is fixed in versions: 1.9.12, 1.10.16, 1.11.17, 1.12.23, 1.13.15, 1.14.18, 2.0.16, 2.1.12, 2.2.3 and above.

Frequently asked questions

What is CVE-2026-31824?
Sylius is an Open Source eCommerce Framework on Symfony. A Time-of-Check To Time-of-Use (TOCTOU) race condition was discovered in the promotion usage limit enforcement. The same class of vulnerability affects the promotion usage limit (the global used counter on Promotion entities), coupon usage limit (the global used counter on PromotionCoupon entities), and coupon per-customer usage limit (the per-customer redemption count on PromotionCoupon entities). In all three cases, the eligibility check reads the used counter (or order count) from an in-memory Doctrine entity during validation, while the actual usage increment in OrderPromotionsUsageModifier happens later during order completion — with no database-level locking or atomic operations between the two phases. Because Doctrine flushes an absolute value (SET used = 1) rather than an atomic increment (SET used = used + 1), and because the affected entities lack optimistic locking, concurrent requests all read the same stale usage counts and pass the eligibility checks simultaneously. An attacker can exploit this by preparing multiple carts with the same limited-use promotion or coupon and firing simultaneous PATCH /api/v2/shop/orders/{token}/complete requests. All requests pass the usage limit checks and complete successfully, allowing a single-use promotion or coupon to be redeemed an arbitrary number of times. The per-customer limit can be bypassed in the same way by a single customer completing multiple orders concurrently. No authentication is required to exploit this vulnerability. This may lead to direct financial loss through unlimited redemption of limited-use promotions and discount coupons. The issue is fixed in versions: 1.9.12, 1.10.16, 1.11.17, 1.12.23, 1.13.15, 1.14.18, 2.0.16, 2.1.12, 2.2.3 and above.
How severe is CVE-2026-31824?
CVE-2026-31824 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.
Is CVE-2026-31824 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31824?
CVE-2026-31824 affects Sylius. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-31824?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-31824 have an EU (EUVD) identifier?
Yes. CVE-2026-31824 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10920.
When was CVE-2026-31824 published?
CVE-2026-31824 was published on 2026-03-10 and last updated on 2026-06-17.

References

Affected products (1)

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