CVE-2026-41281: Cleartext Transmission in あんしんフィルター for au
Platform
android
Component
anshin-filter-for-au
Fixed in
4.9_b0003
CVE-2026-41281 describes a Cleartext Transmission of Sensitive Information vulnerability within the Android application "あんしんフィルター for au," developed by KDDI CORPORATION. This flaw enables a man-in-the-middle (MITM) attacker to potentially intercept and manipulate communications transmitted without encryption. The vulnerability affects versions prior to 4.9b0003, and a fix is available in version 4.9b0003.
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Impact and Attack Scenarios
The primary impact of CVE-2026-41281 is the potential for sensitive data to be exposed or tampered with. A successful MITM attack could allow an attacker to intercept usernames, passwords, personal information, or other confidential data transmitted by the application. This could lead to identity theft, financial loss, or unauthorized access to user accounts. The attacker could also modify the data in transit, potentially injecting malicious content or altering the application's behavior. Given the nature of the vulnerability, the blast radius extends to any user of the application who transmits sensitive information over an insecure network.
Exploitation Context
CVE-2026-41281 was published on May 13, 2026. Severity is currently assessed as Medium. Public proof-of-concept (POC) code is not currently available, but the vulnerability's nature makes it susceptible to exploitation in environments with compromised network infrastructure. The vulnerability is not currently listed on KEV or EPSS, indicating a low to medium probability of active exploitation at this time. Refer to KDDI CORPORATION's advisory for further details.
Threat Intelligence
Exploit Status
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- High — requires a race condition, non-default configuration, or specific circumstances. Harder to exploit reliably.
- Privileges Required
- None — unauthenticated. No login or credentials needed to exploit.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- Low — partial or indirect data access. Attacker gains limited information.
- Integrity
- Low — attacker can modify some data with limited scope or impact.
- Availability
- None — no availability impact. Service remains fully operational.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
Mitigation and Workarounds
The primary mitigation for CVE-2026-41281 is to upgrade the "あんしんフィルター for au" application to version 4.9_b0003 or later. If upgrading is not immediately feasible, consider implementing network-level protections such as VPNs or secure proxies to encrypt communications. While not a direct fix, these measures can reduce the risk of MITM attacks. Regularly monitor network traffic for suspicious activity and implement intrusion detection systems (IDS) to identify potential exploitation attempts. After upgrading, verify the fix by attempting to intercept network traffic between the application and the server to confirm that data is now transmitted securely.
How to fix
Actualice la aplicación あんしんフィルター for au a la versión 4.9_b0003 o posterior para mitigar la vulnerabilidad de transmisión de información confidencial en texto plano. Esto evitará que atacantes intercepten y modifiquen las comunicaciones.
Frequently asked questions
What is CVE-2026-41281 — Cleartext Transmission in あんしんフィルター for au?
CVE-2026-41281 is a Medium severity vulnerability in the "あんしんフィルター for au" app allowing MITM attacks to intercept unencrypted data. It affects versions before 4.9_b0003, potentially exposing sensitive information.
Am I affected by CVE-2026-41281 in あんしんフィルター for au?
You are affected if you are using "あんしんフィルター for au" version 4.9_b0003 or earlier. Check your app version and upgrade immediately to mitigate the risk.
How do I fix CVE-2026-41281 in あんしんフィルター for au?
Upgrade to version 4.9_b0003 or later. If immediate upgrade isn't possible, use VPNs or secure proxies to encrypt network traffic.
Is CVE-2026-41281 being actively exploited?
While no active exploitation is currently confirmed, the vulnerability's nature makes it a potential target. Monitor network traffic and implement detection measures.
Where can I find the official あんしんフィルター for au advisory for CVE-2026-41281?
Refer to KDDI CORPORATION's official security advisory for "あんしんフィルター for au" regarding CVE-2026-41281. Check the KDDI website or app store for updates.
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