CVE-2025-21021 is a medium-severity vulnerability classified as CWE-787 (Out-of-bounds Write) affecting the Samsung Mobile Blockchain Keystore component, specifically in the drawing pinpad functionality prior to version 1.3.17.2. This vulnerability allows a local attacker with elevated privileges to perform an out-of-bounds write in memory. The flaw arises when the pinpad input handling does not properly validate or restrict memory boundaries, enabling the attacker to overwrite adjacent memory regions. Such memory corruption can lead to arbitrary code execution or privilege escalation within the context of the Blockchain Keystore application. The vulnerability requires local access with high privileges (e.g., root or system-level access) and does not require user interaction. The CVSS v3.1 base score is 5.7, reflecting a medium severity with high impact on confidentiality and integrity but no impact on availability. The attack vector is local, and the attack complexity is high, indicating exploitation is not trivial. No known exploits are currently reported in the wild, and no patches or updates have been linked yet. The Blockchain Keystore is a security-critical component managing cryptographic keys for blockchain applications on Samsung mobile devices, making this vulnerability significant for protecting sensitive cryptographic assets and user data.

For European organizations, especially those relying on Samsung mobile devices for blockchain or cryptographic operations, this vulnerability poses a risk of unauthorized access or manipulation of sensitive cryptographic keys stored in the Blockchain Keystore. Successful exploitation could lead to compromise of blockchain wallets, unauthorized transactions, or leakage of confidential cryptographic material, undermining trust in blockchain-based services. Although exploitation requires local privileged access, insider threats or malware with elevated privileges could leverage this vulnerability to escalate privileges or tamper with key storage integrity. This could affect financial institutions, blockchain service providers, and enterprises using Samsung devices for secure blockchain operations. The impact on confidentiality and integrity is high, potentially leading to data breaches or financial fraud. However, the lack of remote exploitability and requirement for high privileges limit the scope of impact to environments where attackers have already gained significant access.

European organizations should prioritize updating Samsung Blockchain Keystore to version 1.3.17.2 or later once available to remediate this vulnerability. Until patches are released, organizations should enforce strict access controls on Samsung devices, limiting administrative privileges to trusted personnel only. Employ mobile device management (MDM) solutions to monitor and restrict installation of unauthorized applications and detect privilege escalation attempts. Regularly audit device security settings and ensure that devices are not rooted or jailbroken, as this increases risk of local privilege abuse. Additionally, implement endpoint detection and response (EDR) tools capable of identifying suspicious local activity indicative of exploitation attempts. For blockchain applications, consider multi-factor authentication and transaction anomaly detection to mitigate risks from potential key compromise. Finally, maintain awareness of Samsung security advisories for timely patch deployment.