CVE-2026-56831

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

September 11, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Sep 15, 2026
Patch available. Sources: github_commit, github_release, github, github_pr.
github_release Patch Available

v2.9.0

Patch available: shopperlabs/shopper v2.9.0

https://github.com/shopperlabs/shopper/releases/tag/v2.9.0
github_commit Patch Available

commit 967e616281de (shopperlabs/shopper)

Patch available: shopperlabs/shopper v2.9.0 (contains commit 967e616281de)

https://github.com/shopperlabs/shopper/commit/967e616281ded1a0050d9102858ecd7dd7f66a41
github_pr Patch Available

fix(discounts): enforce positive discount values across all layers

Patch available: shopperlabs/shopper v2.9.0 (PR #528 merged 2026-06-08)

https://github.com/shopperlabs/shopper/pull/528
github Patch Available

Negative discount values accepted and propagated through order calculation pipeline · Advisory · shopperlabs/shopper · GitHub

https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf

Vendor Advisories for CVE-2026-56831(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
shopper/frameworkv2.0.0 ... v2.8.1 (61 versions)2.9.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 10× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-20 09:30 UTCEG score recompute
  2. 2026-09-19 10:59 UTCEG score recompute
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 12:30 UTCEG score recompute
  5. 2026-09-17 19:31 UTCEPSS rescore
  6. 2026-09-16 15:30 UTCEG score recompute
  7. 2026-09-16 14:52 UTCEG score recompute
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-15 18:36 UTCEG score recompute
  10. 2026-09-11 22:24 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-56831?
CVE-2026-56831 is a medium vulnerability published on September 11, 2026. Shopper is a Headless e-commerce Admin Panel. Prior to 2.9.0, the /cpanel/discounts administrative interface accepts negative fixedamount discount values, persists them in shdiscounts, and passes them through vendor/shopper/cart/src/Discounts/DiscountCalculator.php and…
When was CVE-2026-56831 disclosed?
CVE-2026-56831 was first published in the National Vulnerability Database on September 11, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56831 actively exploited?
CVE-2026-56831 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.4% of all scored CVEs.
What is the CVSS score of CVE-2026-56831?
CVE-2026-56831 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-56831?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56831, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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