How severe is CVE-2021-33577?

CVE-2021-33577 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-33577 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33577?

CVE-2021-33577 affects Cleo Lexicom. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33577?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-33577 published?

CVE-2021-33577 was published on 2021-06-18 and last updated on 2026-06-17.

CVE-2021-33577

CVE-2021-33577 is a medium-severity vulnerability in Cleo Lexicom with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Cleo Lexicom
Published: 2021-06-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-33577?: 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.
How severe is CVE-2021-33577?: CVE-2021-33577 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-33577 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33577?: CVE-2021-33577 affects Cleo Lexicom. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33577?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-33577 published?: CVE-2021-33577 was published on 2021-06-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:cleo:lexicom:5.5.0.0:*:*:*:*:*:*:*

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