CVE-2020-37221: Stack Overflow in Atomic Alarm Clock
Platform
windows
Component
atomic-alarm-clock
CVE-2020-37221 describes a stack overflow vulnerability found in Atomic Alarm Clock version 6.3. This flaw allows a local attacker to execute arbitrary code, potentially gaining control of the system. The vulnerability stems from improper handling of user input in the Time Zones Clock configuration's display name textbox. A fix is available; users are strongly advised to upgrade.
Impact and Attack Scenarios
The primary impact of CVE-2020-37221 is the ability for a local attacker to execute arbitrary code with the privileges of the Atomic Alarm Clock application. This could lead to complete system compromise, data theft, or the installation of malware. Attackers can leverage structured exception handling overwrite and encoded shellcode to bypass SafeSEH protections, making exploitation more reliable. Successful exploitation requires local access to the affected system, but the potential consequences are severe, potentially allowing attackers to escalate privileges and move laterally within the network if the application has elevated permissions.
Exploitation Context
The vulnerability was published on 2026-05-13. Exploitation context is currently limited, and there's no indication of active campaigns targeting this specific vulnerability. The description mentions bypassing SafeSEH protections, which suggests a degree of sophistication required for successful exploitation. It is not currently listed on KEV or EPSS, indicating a low to medium probability of exploitation.
Threat Intelligence
Exploit Status
CISA SSVC
CVSS Vector
What do these metrics mean?
- Attack Vector
- Local — attacker needs a local shell or interactive session on the system.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- 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
- High — complete confidentiality loss. Attacker can read all data: credentials, keys, personal data.
- Integrity
- High — attacker can write, modify, or delete any data: databases, config files, or code.
- Availability
- High — complete crash or resource exhaustion. Full denial of service.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
Mitigation and Workarounds
The primary mitigation for CVE-2020-37221 is to upgrade to a patched version of Atomic Alarm Clock. Since a fixed version is not explicitly mentioned in the provided data, consider reverting to a previous known-good version if the upgrade causes instability. As a temporary workaround, restrict access to the Time Zones Clock configuration to trusted users only. Monitor system logs for suspicious activity related to the application, particularly errors or crashes occurring after user input. While a specific Sigma or YARA rule isn't available, monitor for unusual process creation or network connections originating from the Atomic Alarm Clock process.
How to fix
Actualice Atomic Alarm Clock a una versión corregida. Verifique el sitio web del proveedor o las fuentes de descarga oficiales para obtener la última versión. Como no se proporciona una versión corregida, considere desinstalar la aplicación hasta que se publique una actualización.
Frequently asked questions
What is CVE-2020-37221 — Stack Overflow in Atomic Alarm Clock?
CVE-2020-37221 is a security vulnerability affecting Atomic Alarm Clock version 6.3, allowing a local attacker to execute arbitrary code through a stack overflow in the Time Zones Clock configuration. It has a CVSS score of 8.4 (HIGH).
Am I affected by CVE-2020-37221 in Atomic Alarm Clock?
You are affected if you are running Atomic Alarm Clock version 6.3. Upgrade to a patched version as soon as possible. Check your installed version against known vulnerable versions.
How do I fix CVE-2020-37221 in Atomic Alarm Clock?
The recommended fix is to upgrade to a patched version of Atomic Alarm Clock. If an upgrade is not immediately possible, consider reverting to a previous known-good version or restricting access to the Time Zones Clock configuration.
Is CVE-2020-37221 being actively exploited?
Currently, there is no public information indicating active exploitation of CVE-2020-37221. However, the vulnerability's severity warrants prompt mitigation.
Where can I find the official Atomic Alarm Clock advisory for CVE-2020-37221?
Refer to the Atomic Alarm Clock vendor's website or security advisory page for the official advisory regarding CVE-2020-37221. The publication date is 2026-05-13.
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