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Vulnerability record · CVE-2021-33577 · published 18 June 2021

CVE-2021-33577: Cleo lexicom vulnerability

Cleo · Lexicom

An issue was discovered in Cleo LexiCom 5.5.0.0. The requirement for the sender of an AS2 message to identify themselves (via encryption and signing of the message) can be bypassed by changing the Content-Type of the message to text/plain.

5.3 CVSS 3.1 Medium EPSS 0.59% · top 54.2%
5.3CVSS 3.1 base score, v2 5.0
0.59%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in Cleo LexiCom 5.5.0.0. The requirement for the sender of an AS2 message to identify themselves (via encryption and signing of the message) can be bypassed by changing the Content-Type of the message to text/plain.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/atredispartners/advisories/blob/master/ATREDIS-2020-0011.md ExploitThird Party Advisory
https://www.cleo.com/cleo-lexicom Product
https://github.com/atredispartners/advisories/blob/master/ATREDIS-2020-0011.md ExploitThird Party Advisory
https://www.cleo.com/cleo-lexicom Product

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2024-55956Cleo Harmony, VLTrader and LexiCom unauthenticated command injection via AutorunCleo Harmony, VLTrader and LexiCom before 5.8.0.24 allow an unauthenticated user to import and execute arbitrary Bash or PowerShell commands on the h…KEVEPSS 94%analysed9.8CVE-2024-50623Cleo Harmony, VLTrader, LexiCom Unrestricted File Upload RCECleo Harmony, VLTrader, and LexiCom before 5.8.0.21 allow unrestricted file upload and download, which can lead to remote code execution. The flaw is…KEVEPSS 99%analysed9.8CVE-2021-33576Cleo lexicom path traversal vulnerabilityAn issue was discovered in Cleo LexiCom 5.5.0.0. Within the AS2 message, the sender can specify a filename. This filename can include path-traversal …EPSS 1.5%

Source: NIST National Vulnerability Database (record CVE-2021-33577), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.