How severe is CVE-2020-12821?

CVE-2020-12821 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-2020-12821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12821?

CVE-2020-12821 affects Protocol Gossipsub. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-12821?

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-2020-12821 published?

CVE-2020-12821 was published on 2020-07-07 and last updated on 2026-06-17.

CVE-2020-12821

CVE-2020-12821 is a critical-severity vulnerability in Protocol Gossipsub 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.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Protocol Gossipsub
Published: 2020-07-07
Last modified: 2026-06-17

Description

Gossipsub 1.0 does not properly resist invalid message spam, such as an eclipse attack or a sybil attack.

Frequently asked questions

What is CVE-2020-12821?: Gossipsub 1.0 does not properly resist invalid message spam, such as an eclipse attack or a sybil attack.
How severe is CVE-2020-12821?: CVE-2020-12821 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-2020-12821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12821?: CVE-2020-12821 affects Protocol Gossipsub. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-12821?: 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-2020-12821 published?: CVE-2020-12821 was published on 2020-07-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:protocol:gossipsub:1.0:*:*:*:*:*:*:*

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