How severe is CVE-2021-3801?

CVE-2021-3801 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-3801 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-2021-3801?

CVE-2021-3801 affects Prismjs Prism. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3801?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-3801 published?

CVE-2021-3801 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-3801

CVE-2021-3801 is a medium-severity vulnerability in Prismjs Prism with a CVSS 3.x base score of 6.5. 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-1333.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Prismjs Prism
Published: 2021-09-15
Last modified: 2026-06-17

Description

prism is vulnerable to Inefficient Regular Expression Complexity

Frequently asked questions

What is CVE-2021-3801?: prism is vulnerable to Inefficient Regular Expression Complexity
How severe is CVE-2021-3801?: CVE-2021-3801 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-3801 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-2021-3801?: CVE-2021-3801 affects Prismjs Prism. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3801?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3801 published?: CVE-2021-3801 was published on 2021-09-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:prismjs:prism:*:*:*:*:*:node.js:*:*

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