How severe is CVE-2021-36377?

CVE-2021-36377 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 high, and availability none.

Is CVE-2021-36377 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36377?

CVE-2021-36377 primarily affects Fossil-scm Fossil. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-36377?

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-2021-36377 published?

CVE-2021-36377 was published on 2021-07-12 and last updated on 2026-06-17.

CVE-2021-36377

CVE-2021-36377 is a high-severity vulnerability in Fossil-scm Fossil 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-295.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Fossil-scm Fossil
Published: 2021-07-12
Last modified: 2026-06-17

Description

Fossil before 2.14.2 and 2.15.x before 2.15.2 often skips the hostname check during TLS certificate validation.

Frequently asked questions

What is CVE-2021-36377?: Fossil before 2.14.2 and 2.15.x before 2.15.2 often skips the hostname check during TLS certificate validation.
How severe is CVE-2021-36377?: CVE-2021-36377 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 high, and availability none.
Is CVE-2021-36377 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36377?: CVE-2021-36377 primarily affects Fossil-scm Fossil. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-36377?: 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-2021-36377 published?: CVE-2021-36377 was published on 2021-07-12 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:fossil-scm:fossil:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

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