How severe is CVE-2020-22552?

CVE-2020-22552 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-22552 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-22552?

CVE-2020-22552 affects Snap7 Project Snap7. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-22552?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-22552 published?

CVE-2020-22552 was published on 2020-10-28 and last updated on 2026-07-05.

CVE-2020-22552

CVE-2020-22552 is a high-severity vulnerability in Snap7 Project Snap7 with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Snap7 Project Snap7
Published: 2020-10-28
Last modified: 2026-07-05

Description

The Snap7 server component in version 1.4.1, when an attacker sends a crafted packet with COTP protocol the last-data-unit flag set to No and S7 writes a var function, the Snap7 server will be crashed.

Frequently asked questions

What is CVE-2020-22552?: The Snap7 server component in version 1.4.1, when an attacker sends a crafted packet with COTP protocol the last-data-unit flag set to No and S7 writes a var function, the Snap7 server will be crashed.
How severe is CVE-2020-22552?: CVE-2020-22552 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-22552 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-22552?: CVE-2020-22552 affects Snap7 Project Snap7. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-22552?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-22552 published?: CVE-2020-22552 was published on 2020-10-28 and last updated on 2026-07-05.

References

Affected products (1)

cpe:2.3:a:snap7_project:snap7:1.4.1:*:*:*:*:*:*:*