All vulnerabilities
CVE-2026-77470GHSA-476v-jr53-8rxc

Lychee: Webshop checkout lets the client override the payment `amount` sent to the gateway via malicious crafted POST request

LycheeOrg Lychee
Open in ThreatlineRecord JSON
CVSS
8.3High
ExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 15 Oct 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.45%Chance of exploitation activity in the next 30 days, higher than 38% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published15 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Description

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.

Text from CVE List

Affected versions 2

  • Lycheeaffected: < 7.7.1CVE List
  • lychee-org/lychee, composer<= 7.7.0GitHub

References 4