Listen to this Post
CVE-2026-0100 is a critical vulnerability in Android’s resource loading mechanism (androidfw), enabling local privilege escalation without user interaction. The flaw, a heap buffer overflow in the `Load` function of LoadedArsc.cpp, arises from insufficient validation when parsing malicious Android resource table files (ARSC). Specifically, the `RES_TABLE_TYPE` block contains a `package_count` field that is not properly verified. The exploit unfolds in the following stages:
1. Trigger Condition: An attacker places a specially crafted resource table (ARSC) inside a malicious APK or exploits an already installed app’s resources. When the system’s resource loader parses the `RES_TABLE_TYPE` block, it reads the attacker-controlled `package_count` field.
2. Vulnerable Logic: Inside the `LoadedArsc::Load` function, a `packages_seen` counter is incremented for each processed package. Due to the missing bound check, a `package_count` value that is larger than the allocated heap buffer’s capacity leads the logic to believe that more packages exist than memory can hold. This flawed comparison causes the loader to attempt writing package entries beyond the bounds of the allocated buffer.
3. Memory Corruption: This write operation accesses memory locations outside the intended heap buffer, corrupting adjacent heap metadata or other critical data structures.
4. Privilege Escalation: By carefully controlling the corrupted data, an attacker can overwrite a function pointer or similar control-flow data. This allows them to redirect execution to arbitrary code within the privileged `android` system server process, gaining full system-level privileges.
This heap buffer overflow leads to arbitrary code execution within Android’s system server, allowing an attacker to completely compromise the device.
DailyCVE Form:
Platform: Android
Version: 14, 15, 16, 16-QPR2
Vulnerability: Heap Buffer Overflow
Severity: Critical
date: June 1, 2026
Prediction: June 5, 2026
What Undercode Say:
The vulnerability resides in androidfw/LoadedArsc.cpp. The following pseudo-code demonstrates the missing bound check:
bool LoadedArsc::Load(..., const void data, size_t size) {
...
const ResTable_header header = (const ResTable_header)data;
uint32_t packageCount = dtohl(header->packageCount);
// Vulnerable: No validation of packageCount against remaining buffer size.
mPackages.resize(packageCount);
for (uint32_t i = 0; i < packageCount; i++) {
// Out-of-bounds write if i >= allocated heap buffer size.
mPackages[bash] = new LoadedPackage(...);
}
...
}
Attackers can trigger the overflow by invoking `AssetManager::addAssetPath` on a malicious APK, leading to a crash or code execution.
Exploit:
To exploit this vulnerability, an attacker would:
- Craft a Malicious Resource Table: Using a custom tool, the attacker creates a valid-looking but malicious Android resource table file (ARSC) where the `package_count` field is set to a value that exceeds the allocated heap buffer size.
- Package the Payload: The malicious ARSC is embedded into a seemingly benign APK.
- Deliver and Trigger: The attacker tricks the user into installing the malicious APK or lures them to a website that forces a download. Once installed, the APK calls the `AssetManager` APIs to load its own resources.
- Execute Arbitrary Code: The heap overflow corrupts a function pointer in the system server’s memory. When the system calls that function, it executes the attacker’s code with system-level privileges.
Protection:
Apply Security Patches: Install the June 2026 Android security update, which includes a fix that adds boundary checks for `packages_seen` against package_count.
Source Code Fix: The patched code in `LoadedArsc.cpp` now includes a validation step:
if (packageCount > (size - sizeof(ResTable_header)) / sizeof(ResTable_package_header)) {
// Handle error: invalid resource table.
return BAD_TYPE;
}
Mitigation: Until patching, users should avoid installing applications from untrusted sources and consider using Android’s built-in Play Protect feature.
Impact:
This vulnerability is critical as it allows a local, unprivileged attacker to execute arbitrary code within the system server, leading to full device compromise. An attacker could silently install persistent spyware, steal sensitive data, or perform any action the device owner can, without requiring any user interaction beyond initial app installation.
🎯Let’s Practice Exploiting & Learn Patching For Free:
🎓 Live Courses & Certifications:
Join Undercode Academy for Verified Certifications
🚀 Request a Custom Project:
Secure, high-velocity infrastructure and disruptive technological engineering. Contact our engineering team for high-tier development and proprietary systems:
[email protected]
💎 Smart Architecture | 🛡️ Secure by Design | ⭐ Trusted by Thousands
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
