How severe is CVE-2020-15138?

CVE-2020-15138 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2020-15138 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15138?

CVE-2020-15138 affects Prismjs Previewers. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-15138?

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-2020-15138 published?

CVE-2020-15138 was published on 2020-08-07 and last updated on 2026-06-17.

CVE-2020-15138

CVE-2020-15138 is a high-severity vulnerability in Prismjs Previewers with a CVSS 3.x base score of 7.1. 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-79.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 2.6
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Prismjs Previewers
Published: 2020-08-07
Last modified: 2026-06-17

Description

Prism is vulnerable to Cross-Site Scripting. The easing preview of the Previewers plugin has an XSS vulnerability that allows attackers to execute arbitrary code in Safari and Internet Explorer. This impacts all Safari and Internet Explorer users of Prism >=v1.1.0 that use the _Previewers_ plugin (>=v1.10.0) or the _Previewer: Easing_ plugin (v1.1.0 to v1.9.0). This problem is fixed in version 1.21.0. To workaround the issue without upgrading, disable the easing preview on all impacted code blocks. You need Prism v1.10.0 or newer to apply this workaround.

Frequently asked questions

What is CVE-2020-15138?: Prism is vulnerable to Cross-Site Scripting. The easing preview of the Previewers plugin has an XSS vulnerability that allows attackers to execute arbitrary code in Safari and Internet Explorer. This impacts all Safari and Internet Explorer users of Prism >=v1.1.0 that use the _Previewers_ plugin (>=v1.10.0) or the _Previewer: Easing_ plugin (v1.1.0 to v1.9.0). This problem is fixed in version 1.21.0. To workaround the issue without upgrading, disable the easing preview on all impacted code blocks. You need Prism v1.10.0 or newer to apply this workaround.
How severe is CVE-2020-15138?: CVE-2020-15138 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2020-15138 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15138?: CVE-2020-15138 affects Prismjs Previewers. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-15138?: 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-2020-15138 published?: CVE-2020-15138 was published on 2020-08-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:prismjs:previewers:*:*:*:*:*:prismjs:*:*

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