CVE-2026-77470 LycheeOrg CVE debrief

Who should care

Defenders responsible for Lychee webshop installations, especially those with enabled webshops and purchasable items, should assess their exposure and prioritize verification and remediation efforts.

Why it matters

CVE-2026-77470 is a high-severity vulnerability in Lychee that allows unauthenticated buyers to tamper with payment amounts during webshop checkout. Defenders responsible for Lychee webshop installations should assess their exposure, prioritize verification and remediation efforts, and implement compensating controls to detect and prevent potential payment tampering.

• Potential payment tampering and financial loss
• Possible auto-fulfillment of goods while underpaying the merchant
• Need for verification of Lychee webshop installations and Omnipay gateway configurations
• Potential reputational damage due to payment security incident

Technical summary

The Lychee webshop checkout process is vulnerable to payment tampering due to an unrestricted additional_data array being accepted and merged with server-computed purchase parameters. This allows an unauthenticated buyer to replace the amount, currency, returnUrl, cancelUrl, or transactionId before the payment parameters are passed to a non-PayPal Omnipay gateway. The issue requires an enabled webshop, a purchasable item, and an affected Omnipay gateway. Defenders should prioritize verifying exposure of Lychee webshop installations, especially those with enabled webshops and purchasable items, and ensure they are running version 7.7.1 or later.

Defensive priority

Defenders should prioritize verifying exposure of Lychee webshop installations, especially those with enabled webshops and purchasable items, and ensure they are running version 7.7.1 or later. They should also monitor for suspicious payment transactions and implement compensating controls to detect and prevent potential payment tampering.

Recommended defensive actions

• Verify Lychee webshop installations for exposure and update to version 7.7.1 or later
• Monitor for suspicious payment transactions and implement compensating controls
• Review and update inventory checks for Lychee webshop installations
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and the fixed version. However, there is limited information on the affected Omnipay gateways and potential exploitation.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.