CVE-2026-56831
Shopper: Negative discount values accepted and propagated through order calculation pipeline
Description
Shopper is a Headless e-commerce Admin Panel. Prior to 2.9.0, the /cpanel/discounts administrative interface accepts negative fixed_amount discount values, persists them in sh_discounts, and passes them through vendor/shopper/cart/src/Discounts/DiscountCalculator.php and vendor/shopper/cart/src/Pipelines/Calculate.php without enforcing a positive-value invariant. Because the calculation subtracts discountTotal from the subtotal, a negative discount increases the resulting order total instead of reducing it. Malformed discount records can therefore cause incorrect pricing and financial data integrity failures, although the advisory does not establish a customer-facing exploitation path. This issue is fixed in version 2.9.0.
INFO
Published Date :
Sept. 15, 2026, 6:17 p.m.
Last Modified :
Sept. 30, 2026, 5:51 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | github | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Validate discount values are positive before saving.
- Validate percentage discounts are between 0 and 100.
- Sanitize existing discount records before calculation.
- Update discount calculation logic.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56831.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56831 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56831
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56831 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56831 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 16, 2026
Action Type Old Value New Value Added Reference https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf Added SSVC {'id': 'CVE-2026-56831', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-16T14:41:46.439666Z'} -
New CVE Received by [email protected]
Sep. 15, 2026
Action Type Old Value New Value Added Description Shopper is a Headless e-commerce Admin Panel. Prior to 2.9.0, the /cpanel/discounts administrative interface accepts negative fixed_amount discount values, persists them in sh_discounts, and passes them through vendor/shopper/cart/src/Discounts/DiscountCalculator.php and vendor/shopper/cart/src/Pipelines/Calculate.php without enforcing a positive-value invariant. Because the calculation subtracts discountTotal from the subtotal, a negative discount increases the resulting order total instead of reducing it. Malformed discount records can therefore cause incorrect pricing and financial data integrity failures, although the advisory does not establish a customer-facing exploitation path. This issue is fixed in version 2.9.0. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Added CWE CWE-20 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/56xxx/CVE-2026-56831.json">CVE-2026-56831</a> Added Reference https://github.com/shopperlabs/shopper/commit/967e616281ded1a0050d9102858ecd7dd7f66a41 Added Reference https://github.com/shopperlabs/shopper/pull/528 Added Reference https://github.com/shopperlabs/shopper/releases/tag/v2.9.0 Added Reference https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf