# CVE-2026-21128: Samsung Checkout improper input validation in CreditCardRegisterActivity

Source: https://junglewise.ai/threats/cve-2026-21128-improper-input-validation-in-creditcardregisteractivity-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-21128 · Severity: info · Published 2026-10-12

Samsung Checkout is a payment processing application used by Android users to handle credit card transactions. A flaw in its input validation allows a local attacker to launch arbitrary activities with the app's elevated privileges, potentially intercepting or modifying payment operations or accessing sensitive financial data.

Technologies: [Samsung Checkout](https://junglewise.ai/threats/technologies/samsung-checkout). Vendors: [Samsung](https://junglewise.ai/threats/vendors/samsung).

## Quick answers

**Is CVE-2026-21128 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-21128 being exploited in the wild.

**How severe is CVE-2026-21128?** Informational severity, published 12 October 2026.

**Which products and versions are affected?** Samsung Checkout prior to 5.1.03.1.

**Is there a fix for CVE-2026-21128?** Yes: fixed in 5.1.03.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-21128 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-21128?** Check whether you run Samsung Checkout at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 5.1.03.1

## Technical details

The CreditCardRegisterActivity component in Samsung Checkout fails to properly validate user-supplied input prior to version 5.1.03.1, enabling a local attacker to trigger unintended activity execution with the application's system privileges. This requires local access to the device but does not require user interaction. A successful exploit could allow arbitrary code execution or data theft within the payment application's context.

## Affected products

- Samsung Checkout prior to 5.1.03.1

## Timeline

- 2026-10-12: disclosed

## References

- [https://security.samsungmobile.com/serviceWeb.smsb?year=2026&month=10](https://security.samsungmobile.com/serviceWeb.smsb?year=2026&month=10)

## Related threats

- [Samsung Checkout improper input validation in activity launch](https://junglewise.ai/threats/cve-2026-21130-improper-input-validation-in-creditcardretrieveactivity-of)
- [Samsung Checkout improper input validation in activity](https://junglewise.ai/threats/cve-2026-21129-improper-input-validation-in-guestcreditcardregisteractivity-of)