How severe is CVE-2020-11939?

CVE-2020-11939 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-11939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-11939?

CVE-2020-11939 affects Ntop Ndpi. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-11939?

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

When was CVE-2020-11939 published?

CVE-2020-11939 was published on 2020-04-23 and last updated on 2026-06-17.

CVE-2020-11939

CVE-2020-11939 is a critical-severity vulnerability in Ntop Ndpi with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Ntop Ndpi
Published: 2020-04-23
Last modified: 2026-06-17

Description

In nDPI through 3.2 Stable, the SSH protocol dissector has multiple KEXINIT integer overflows that result in a controlled remote heap overflow in concat_hash_string in ssh.c. Due to the granular nature of the overflow primitive and the ability to control both the contents and layout of the nDPI library's heap memory through remote input, this vulnerability may be abused to achieve full Remote Code Execution against any network inspection stack that is linked against nDPI and uses it to perform network traffic analysis.

Frequently asked questions

What is CVE-2020-11939?: In nDPI through 3.2 Stable, the SSH protocol dissector has multiple KEXINIT integer overflows that result in a controlled remote heap overflow in concat_hash_string in ssh.c. Due to the granular nature of the overflow primitive and the ability to control both the contents and layout of the nDPI library's heap memory through remote input, this vulnerability may be abused to achieve full Remote Code Execution against any network inspection stack that is linked against nDPI and uses it to perform network traffic analysis.
How severe is CVE-2020-11939?: CVE-2020-11939 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-11939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-11939?: CVE-2020-11939 affects Ntop Ndpi. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-11939?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-11939 published?: CVE-2020-11939 was published on 2020-04-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ntop:ndpi:*:*:*:*:*:*:*:*

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