CommuniCrypt Mail <= 1.16 ANSMTP/AOSMTP ActiveX Control Buffer Overflow

published 2025-08-21 14 mo ago modified 2026-06-16 4 mo ago also EUVD-2010-5321

cvss: 8.6; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.7%; EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits: 1; Metasploit

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.

Timeline

2010-05-19 First public exploit (Metasploit exploit/windows/browser/communicrypt_mail_activex)
2025-08-21 Published

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 14 mo ago (2025-08-22)

Exploit prediction

1.69% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

Metasploit exploit/windows/browser/communicrypt_mail_activex CommuniCrypt Mail 1.16 SMTP ActiveX Stack Buffer Overflow metasploit exploit, great rank, 2010-05-19
raw.githubusercontent.com https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/windows/browser/communicrypt_mail_activex.rb referenced PoC, tagged "exploit" by a source, unverified
exploit-db.com https://www.exploit-db.com/exploits/12663 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	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
CNA	4.0	8.6	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

CommuniCrypt Software CommuniCrypt Mail

Classification

Weakness

CWE-121 Stack-based Buffer Overflow

References

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

Sources

CVE List CVE-2010-20119
NVD CVE-2010-20119

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary