CVE-2021-33576Network attack vector

Arbitrary file write via AS2 filename traversal

Published Jun 18, 2021 · Updated Aug 3, 2024

Path traversal in Cleo LexiCom 5.5.0.0 allows remote attackers to write files to arbitrary disk locations via an AS2 filename. The AS2 message handler accepts sender-controlled filenames containing traversal sequences and uses them as output paths without confining the resolved path to the intended directory. A crafted AS2 message is sufficient, while filesystem permissions assigned to the LexiCom process bound the writable locations.

CVSS severity9.8
Critical
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Cleo LexiCom 5.5.0.0 allows remote attackers to write files to arbitrary disk locations via an AS2 filename. The AS2 message handler accepts sender-controlled filenames containing traversal sequences and uses them as output paths without confining the resolved path to the intended directory. A crafted AS2 message is sufficient, while filesystem permissions assigned to the LexiCom process bound the writable locations.

The record

CVE
CVE-2021-33576
Published
Jun 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1105
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1105Ingress Tool Transfer

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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