How severe is CVE-2022-2166?

CVE-2022-2166 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-2022-2166 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-2166?

CVE-2022-2166 primarily affects Joinmastodon Mastodon. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2022-2166?

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-2022-2166 published?

CVE-2022-2166 was published on 2022-11-16 and last updated on 2026-06-17.

CVE-2022-2166

CVE-2022-2166 is a critical-severity vulnerability in Joinmastodon Mastodon 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-307.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-307
Affected product: Joinmastodon Mastodon
Published: 2022-11-16
Last modified: 2026-06-17

Description

Improper Restriction of Excessive Authentication Attempts in GitHub repository mastodon/mastodon prior to 4.0.0.

Frequently asked questions

What is CVE-2022-2166?: Improper Restriction of Excessive Authentication Attempts in GitHub repository mastodon/mastodon prior to 4.0.0.
How severe is CVE-2022-2166?: CVE-2022-2166 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-2022-2166 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-2166?: CVE-2022-2166 primarily affects Joinmastodon Mastodon. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-2166?: 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-2022-2166 published?: CVE-2022-2166 was published on 2022-11-16 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*
cpe:2.3:a:joinmastodon:mastodon:4.0.0:rc1:*:*:*:*:*:*
cpe:2.3:a:joinmastodon:mastodon:4.0.0:rc2:*:*:*:*:*:*
cpe:2.3:a:joinmastodon:mastodon:4.0.0:rc3:*:*:*:*:*:*
cpe:2.3:a:joinmastodon:mastodon:4.0.0:rc4:*:*:*:*:*:*

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