How severe is CVE-2021-42139?

CVE-2021-42139 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-2021-42139 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-2021-42139?

CVE-2021-42139 affects Deno Deno Standard Modules. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42139?

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-2021-42139 published?

CVE-2021-42139 was published on 2021-10-11 and last updated on 2026-06-17.

CVE-2021-42139

CVE-2021-42139 is a critical-severity vulnerability in Deno Deno Standard Modules 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-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Deno Deno Standard Modules
Published: 2021-10-11
Last modified: 2026-06-17

Description

Deno Standard Modules before 0.107.0 allows Code Injection via an untrusted YAML file in certain configurations.

Frequently asked questions

What is CVE-2021-42139?: Deno Standard Modules before 0.107.0 allows Code Injection via an untrusted YAML file in certain configurations.
How severe is CVE-2021-42139?: CVE-2021-42139 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-2021-42139 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-2021-42139?: CVE-2021-42139 affects Deno Deno Standard Modules. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42139?: 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-2021-42139 published?: CVE-2021-42139 was published on 2021-10-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:deno:deno_standard_modules:*:*:*:*:*:*:*:*

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