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TI-2026-74848 Aliases CVE-2026-77470

Lychee webshop checkout lets buyers override payment amount

Priority HIGH 69CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Tampering
Confidentiality · integrity · availability
Low · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-915.

Summary

Lychee before 7.7.1 has an input validation flaw in the Supporter or Pro webshop checkout (CWE-20). Client-supplied additional data overwrites server-computed payment parameters. An unauthenticated buyer can change the amount sent to a non-PayPal Omnipay gateway, which accepts the underpayment and fulfills the goods automatically. Exploitation requires an enabled webshop, a purchasable item and an affected gateway.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Lychee is a free, open-source photo-management tool. Prior to 7.7.1, the Supporter or Pro webshop POST /api/v2/Shop/Checkout/Process flow accepts an unrestricted additional_data array and CheckoutService::preparePurchaseParameters() merges it after server-computed purchase parameters. Because later string keys overwrite earlier keys, an unauthenticated buyer can replace amount, currency, returnUrl, cancelUrl, or transactionId before CheckoutService::processPayment() passes the parameters to a non-PayPal Omnipay gateway. An attacker can therefore make a gateway accept a successful payment for an attacker-selected amount and obtain auto-fulfilled goods while underpaying the merchant. The issue requires an enabled webshop, a purchasable item, and an affected Omnipay gateway. This issue is fixed in version 7.7.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00451 39th percentileScored 2026-11-07
Fix Fixed Lychee (LycheeOrg): 7.7.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LycheeOrgLycheebefore 7.7.17.7.1Patch availableCNA
  • Lychee VendorLycheeOrg Affected before 7.7.1 Fixed in 7.7.1 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:lycheeorg:lychee:*:*:*:*:*:*:*:*——LycheeOrg
  • cpe:2.3:a:lycheeorg:lychee:*:*:*:*:*:*:*:* Versions — — ·LycheeOrg

Remediation

Upgrade Lychee to version 7.7.1, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Lychee (LycheeOrg) Fixed in 7.7.1

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-77470

References

Other 4

  • TI-2026-74843 Album password bypass in Lychee ZIP downloads CVSS 4.0HIGH 8.2
  • TI-2026-74842 Missing rate limiting in Lychee album unlock allows password guessing CVSS 3.1HIGH 7.5
  • TI-2024-16953 Cross-site Request Forgery (CSRF) vulnerability in Lychee version 3.1.6, allows remote… CVSS 3.1HIGH 8.3
  • TI-2026-74845 Payment bypass in Lychee webshop through unrestricted Dummy gateway CVSS 4.0HIGH 8.3
  • TI-2026-74846 Uncontrolled resource consumption in Lychee PDF processing CVSS 4.0HIGH 7.1
  • TI-2024-16952 Cross Site Scripting (XSS) vulnerability in Lychee 3.1.6, allows remote attackers to… CVSS 3.1MEDIUM 6.1
See all 20 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences