CVE-2021-40978
CVE-2021-40978 is a high-severity vulnerability in Mkdocs with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 15% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-22.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v2: 5.0
- EPSS exploit prediction: 15% (96th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-22
- Affected product: Mkdocs
- Published:
- Last modified:
Description
The mkdocs 1.2.2 built-in dev-server allows directory traversal using the port 8000, enabling remote exploitation to obtain :sensitive information. NOTE: the vendor has disputed this as described in https://github.com/mkdocs/mkdocs/issues/2601.] and https://github.com/nisdn/CVE-2021-40978/issues/1
Frequently asked questions
- What is CVE-2021-40978?
- The mkdocs 1.2.2 built-in dev-server allows directory traversal using the port 8000, enabling remote exploitation to obtain :sensitive information. NOTE: the vendor has disputed this as described in https://github.com/mkdocs/mkdocs/issues/2601.] and https://github.com/nisdn/CVE-2021-40978/issues/1
- How severe is CVE-2021-40978?
- CVE-2021-40978 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 high, integrity none, and availability none.
- Is CVE-2021-40978 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-40978?
- CVE-2021-40978 affects Mkdocs. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-40978?
- 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-2021-40978 published?
- CVE-2021-40978 was published on 2021-10-07 and last updated on 2026-06-17.
References
- https://github.com/mkdocs/mkdocs
- https://github.com/mkdocs/mkdocs/issues/2601
- https://github.com/nisdn/CVE-2021-40978
- https://github.com/nisdn/CVE-2021-40978/issues/1
Affected products (1)
- cpe:2.3:a:mkdocs:mkdocs:1.2.2:*:*:*:*:*:*:*
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