CVE-2026-0039: Android Integer Overflow Denial of Service Vulnerability

Technical summary

The vulnerability stems from improper integer overflow handling in ubsan_throwing_runtime.cpp within the Android codebase. CWE-190 (Integer Overflow or Wraparound) is the root cause; when integer arithmetic operations exceed buffer or data type boundaries without validation, they can trigger unhandled exceptions or system instability. An authenticated attacker can invoke this overflow condition remotely, causing persistent denial of service. The CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) indicates network-level exploitability with low attack complexity and moderate authentication requirements, with high availability impact.

Business impact

This vulnerability enables service disruption for organizations dependent on Android devices. Mobile workforces, IoT deployments, and managed device fleets face operational downtime if exploited. Unlike data-theft vulnerabilities, the impact is availability-focused: affected devices become unavailable rather than compromised. For enterprises, this translates to lost productivity, support overhead, and potential SLA violations. The low barrier to exploitation—no user interaction required—increases organizational risk if employee or managed devices are exposed to untrusted networks.

Affected systems

Google Android across multiple versions is affected. Verify the exact release versions and patch timelines by consulting Google's official Android security bulletin and the respective vendor advisory; the vulnerability impacts core runtime functionality, suggesting broad Android deployments are potentially in scope.

Exploitability

Exploitability is moderate to high in practice. The attack requires network access and valid authentication credentials, which raises the bar compared to unauthenticated exploits but is not prohibitively difficult in enterprise or shared-network environments. No user interaction is required once the attacker is authenticated. The low attack complexity means exploitation does not require specialized techniques or timing windows. However, the vulnerability is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, suggesting active in-the-wild exploitation has not yet been publicly documented at publication time.

Remediation

Apply the security patch released by Google for Android as soon as it becomes available. Google typically releases Android security patches monthly; check your device manufacturer's support page for availability and deployment timelines. Enterprises should prioritize patching for devices that operate in multi-user or untrusted network environments, where authenticated attackers are more likely to be present. Interim mitigation: restrict network access to vulnerable devices or monitor for unusual crash patterns that may indicate exploitation attempts.

Patch guidance

Monitor Google's Android Security & Privacy Year in Review and monthly security bulletins for the specific patch version addressing CVE-2026-0039. Patch availability varies by device manufacturer and carrier. For enterprise deployments, coordinate with your device management platform (MDM) to automate rollout once patches are validated in your environment. Test patches on a pilot set of devices before full deployment to ensure compatibility with your applications and infrastructure.

Detection guidance

Monitor for repeated crashes or reboots in ubsan_throwing_runtime.cpp or processes invoking it, which may indicate exploitation attempts. Network-level detection is challenging since the attack is authenticated and does not typically produce distinctive network signatures. Log authentication events to identify suspicious or repeated login attempts preceding crashes. On Android Enterprise devices, use MDM telemetry to flag devices with elevated crash rates or repeated restarts following authentication events.

Why prioritize this

This vulnerability warrants prompt but measured prioritization. The CVSS score of 6.5 (MEDIUM) reflects the authentication requirement, which reduces exposure compared to unauthenticated flaws. However, the absence of attack complexity and the prevalence of Android in mobile workforces mean many organizations have exposed attack surface. Prioritize patching for devices in high-risk roles (finance, healthcare, critical infrastructure) and devices used in shared or untrusted networks. The lack of active exploitation to date provides a window for methodical patching before threat actors shift focus to this vector.

Risk score, explained

The CVSS 3.1 score of 6.5 reflects a Medium-severity vulnerability with high availability impact but limited scope (single device, no data confidentiality or integrity loss). Authentication is required, reducing the likelihood of mass exploitation compared to unauthenticated flaws. The score is appropriate for an internal-network or employee-access scenario; however, in environments where untrusted users can obtain credentials or where devices operate on shared networks, the practical risk may be elevated. Organizations should weigh their specific network topology, authentication mechanisms, and device exposure when assigning internal risk ratings.

Frequently asked questions