CVE-2020-21503Public exploitNetwork attack vector

Free gift redemption via negative credit value

Published Oct 5, 2021 · Updated Aug 4, 2024

Business logic flaw in waimai Super Cms 20150505 allows attackers to obtain gift products for free via a crafted credit parameter. The gift redemption handler at index.php?m=gift&a=addsave accepts a client-supplied credit value of -1 instead of calculating and validating the required price server-side. Published sources do not state whether an account is required; the demonstrated consequence is acquisition of a gift product without spending points.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Business logic flaw in waimai Super Cms 20150505 allows attackers to obtain gift products for free via a crafted credit parameter. The gift redemption handler at index.php?m=gift&a=addsave accepts a client-supplied credit value of -1 instead of calculating and validating the required price server-side. Published sources do not state whether an account is required; the demonstrated consequence is acquisition of a gift product without spending points.

The record

CVE
CVE-2020-21503
Published
Oct 5, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-668, T1565
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1565Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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