CVE-2026-21135 in Internet
Summary
by MITRE • 10/12/2026
Improper access control in Samsung Internet prior to version 30.0.5.6 allows local attackers to access sensitive information.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified as an improper access control flaw within Samsung Internet versions preceding 30.0.5.6 represents a significant security deficiency that undermines the fundamental principle of least privilege expected in mobile operating systems and browser environments. This specific weakness allows local attackers, typically defined as malicious applications or processes running on the same device with limited privileges, to bypass intended restrictions and retrieve sensitive information stored within the browser's context. In modern Android ecosystems, browsers are designed to operate within isolated sandboxes to prevent cross-application data leakage. However, this flaw indicates a breakdown in those isolation mechanisms, potentially exposing user credentials, browsing history, cookies, or cached web content to unauthorized local entities that should not have access to such private data.
From a technical perspective, improper access control vulnerabilities often stem from misconfigured permissions, insufficient validation of the calling process's identity, or flawed logic in how internal APIs handle requests for sensitive resources. In the context of Samsung Internet, this may involve specific components handling storage retrieval or session management failing to verify that the requesting entity possesses the necessary authorization level. When a local attacker exploits this flaw, they are not necessarily gaining root access or full system compromise but rather achieving unauthorized read access to data protected by the browser's internal security model. This type of vulnerability is particularly dangerous because it can be exploited without requiring user interaction beyond the initial installation and execution of the malicious application, making it difficult for users to detect that their private information has been exfiltrated.
The operational impact of this vulnerability extends beyond simple data leakage. If sensitive authentication tokens or session cookies are accessed by a local attacker, they could potentially hijack active sessions on web services where the user is logged in via Samsung Internet. This leads to account takeover scenarios even if strong multi-factor authentication is enabled for remote access, as the stolen credentials might allow bypassing of certain security checks depending on how those services handle session validation. Furthermore, exposure of browsing history and cached content can lead to privacy violations, revealing personal interests, health information, financial activities, or other sensitive details that users expect remain private within their browser profile. This erosion of trust in mobile browsers highlights the critical importance of robust sandboxing and strict access control policies in application development.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) category CWE-269, which covers Improper Privilege Management, specifically where a process does not properly enforce its own security policy or fails to validate permissions before performing sensitive operations. It also relates to CWE-732, concerning Incorrect Permission Assignment for Critical Resource, suggesting that the files or memory segments containing user data were assigned overly permissive access rights within the application's local environment. From an offensive security perspective, this behavior is consistent with techniques observed in ATT&CK framework subcategories related to Local Data Staging and Unsecured Credentials, where attackers seek to harvest sensitive information from local storage for subsequent use in lateral movement or further exploitation attempts against connected accounts.
Mitigation strategies primarily involve the immediate update of Samsung Internet to version 30.0.5.6 or later, as this release contains patches that correct the underlying access control logic and reinforce sandbox boundaries. For users unable to update immediately due to device compatibility constraints, restricting app permissions through Android's permission management settings can provide a partial layer of defense by limiting what local applications can query from other apps' storage areas. Additionally, enabling strict content security policies within web pages served via the browser helps mitigate potential downstream exploitation if any cross-site scripting vulnerabilities are present alongside this access control flaw. Security researchers and developers must ensure that all internal APIs enforce rigorous identity verification before granting access to sensitive data structures, adhering strictly to defense-in-depth principles to prevent local privilege escalation or information disclosure attacks in mobile environments.