How severe is CVE-2021-36798?

CVE-2021-36798 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-2021-36798 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36798?

CVE-2021-36798 primarily affects Helpsystems Cobalt Strike. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-36798?

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-2021-36798 published?

CVE-2021-36798 was published on 2021-08-09 and last updated on 2026-06-17.

CVE-2021-36798

CVE-2021-36798 is a high-severity vulnerability in Helpsystems Cobalt Strike 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. The underlying weakness is classified as CWE-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Helpsystems Cobalt Strike
Published: 2021-08-09
Last modified: 2026-06-17

Description

A Denial-of-Service (DoS) vulnerability was discovered in Team Server in HelpSystems Cobalt Strike 4.2 and 4.3. It allows remote attackers to crash the C2 server thread and block beacons' communication with it.

Frequently asked questions

What is CVE-2021-36798?: A Denial-of-Service (DoS) vulnerability was discovered in Team Server in HelpSystems Cobalt Strike 4.2 and 4.3. It allows remote attackers to crash the C2 server thread and block beacons' communication with it.
How severe is CVE-2021-36798?: CVE-2021-36798 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-2021-36798 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36798?: CVE-2021-36798 primarily affects Helpsystems Cobalt Strike. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-36798?: 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-2021-36798 published?: CVE-2021-36798 was published on 2021-08-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:helpsystems:cobalt_strike:4.2:*:*:*:*:*:*:*
cpe:2.3:a:helpsystems:cobalt_strike:4.3:*:*:*:*:*:*:*

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