CVE-2025-21044 in Samsung
Summary
by MITRE • 10/10/2025
Out-of-bounds write in fingerprint trustlet prior to SMR Oct-2025 Release 1 allows local privileged attackers to write out-of-bounds memory.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/24/2025
This vulnerability represents a critical out-of-bounds write flaw within the fingerprint trustlet component of mobile device security systems. The trustlet operates as a privileged security module that handles biometric authentication data and maintains cryptographic keys for fingerprint verification processes. The issue specifically affects devices prior to the SMR October 2025 security release, indicating this represents a known weakness that was addressed in subsequent updates. The vulnerability allows local privileged attackers to execute memory corruption operations beyond the intended boundaries of the trustlet's memory allocation.
The technical implementation of this flaw stems from inadequate bounds checking within the fingerprint trustlet's memory management routines. When processing fingerprint data or authentication requests, the trustlet fails to properly validate input parameters against allocated memory buffers. This allows an attacker with local privileged access to manipulate memory locations beyond the trustlet's designated operational boundaries. The out-of-bounds write can potentially overwrite critical security data structures, cryptographic keys, or execution control information within the trustlet's memory space.
From an operational impact perspective, this vulnerability significantly compromises the integrity of the device's biometric security infrastructure. Local privileged attackers could exploit this weakness to gain unauthorized access to fingerprint data, potentially enabling credential theft or bypass of authentication mechanisms. The attack vector requires local privileged access, which typically means the attacker must already have elevated system permissions or be running malicious code with sufficient privileges to interact with the trustlet. However, the privilege escalation potential remains high as this vulnerability can be leveraged to corrupt security-critical components that protect the device's authentication system.
The vulnerability aligns with CWE-787 Out-of-bounds Write, which specifically addresses memory corruption issues where programs write data beyond the boundaries of allocated buffers. This weakness is particularly dangerous in security contexts where trustlets operate as isolated security domains with elevated privileges. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, where attackers leverage software vulnerabilities to gain higher-level system access. Additionally, this vulnerability can be classified under T1552 as it potentially exposes sensitive biometric data and cryptographic keys that are protected by the trustlet's security model.
Mitigation strategies should focus on immediate deployment of the SMR October 2025 security release, which contains the necessary patches to address the bounds checking deficiencies. Organizations should also implement monitoring for suspicious memory access patterns and unauthorized trustlet interactions. Device manufacturers should conduct thorough code reviews of all security components to identify similar bounds checking issues. Security teams should also consider implementing runtime protection mechanisms such as memory protection boundaries and stack canaries to detect and prevent exploitation attempts. Regular security assessments of trustlet implementations should be conducted to ensure proper memory management and prevent similar vulnerabilities from emerging in future releases.