CVE-2026-28590 in Android
Summary
by MITRE • 09/08/2026
In multiple locations, there is a possible improper encryption key validation due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described constitutes a critical flaw within the cryptographic implementation, specifically categorized under CWE-327: Use of a Broken or Risky Cryptographic Algorithm and CWE-14: Compiler Removal of Code to Clear Buffers if misapplied in key management contexts, though more accurately it aligns with CWE-695: Use of Low-Level Functionality that fails to properly validate encryption keys. This logic error indicates that the software does not rigorously verify the integrity, format, or origin of cryptographic keys before utilizing them for sensitive operations. In a secure system, key validation is paramount; without it, an attacker can manipulate the input parameters passed to the cryptographic functions. The absence of strict validation allows for scenarios where malformed, truncated, or maliciously crafted keys are accepted by the application logic as valid credentials or encryption material. This failure in defensive programming creates a significant attack surface that does not require complex exploitation techniques but rather precise manipulation of data structures interacting with the key handling routines.
From an operational perspective, this flaw enables local privilege escalation without requiring additional execution privileges from the attacker's context. This means that any user account on the system, even one with minimal permissions such as a standard guest or service account, can potentially exploit this logic error to gain higher-level access, typically administrative or root privileges. The fact that no user interaction is needed for exploitation significantly increases the severity of the vulnerability. It transforms what might have been an interactive attack vector into a fully automated remote or local triggerable event depending on how the vulnerable component is exposed. If the affected service runs with elevated privileges and listens to network connections, this could theoretically be leveraged in conjunction with other vulnerabilities to achieve remote code execution, but even as a standalone issue, it allows for immediate lateral movement within a compromised host by escalating from a low-privilege user to an administrator account locally.
The technical mechanism likely involves the application accepting key material that bypasses expected length checks, format validations, or checksum verifications. For instance, if the code expects a 256-bit AES key but fails to verify that the provided input is exactly thirty-two bytes long and contains only valid hexadecimal characters, an attacker might supply a shorter or malformed string. Depending on how the underlying cryptographic library handles this invalid input, it may truncate the key, use default values, or behave unpredictably in ways that bypass authentication checks or decrypt sensitive data structures incorrectly. This improper validation often stems from legacy code paths where security assumptions were made based on trusted inputs rather than explicit verification of all boundary conditions and edge cases. The logic error essentially creates a gap between the intended security policy and the actual runtime behavior, allowing an unauthenticated local user to bypass access controls that rely on these cryptographic mechanisms for authentication or authorization decisions.
Mitigation strategies must focus on hardening the key management lifecycle within the application. Developers should implement strict input validation routines that enforce exact length requirements, character set restrictions, and structural integrity checks before any cryptographic operation is initiated. Utilizing established cryptographic libraries rather than custom implementations reduces the risk of such logic errors, as these libraries are typically audited for common pitfalls like padding oracle attacks or key injection flaws. Additionally, implementing defense-in-depth measures such as least privilege principles ensures that even if an attacker successfully exploits this vulnerability to escalate privileges, their ability to persist or move laterally is constrained by other security controls. Regular code audits focusing on cryptographic implementations and the integration of static analysis tools configured to detect improper validation patterns can help identify similar issues before deployment. Furthermore, ensuring that services run with minimal necessary permissions limits the impact of any successful privilege escalation attempt, reducing the overall risk profile of the system against this specific class of vulnerabilities.