How severe is CVE-2021-39307?

CVE-2021-39307 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-39307 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39307?

CVE-2021-39307 affects Pdftron Webviewer Ui. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39307?

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

When was CVE-2021-39307 published?

CVE-2021-39307 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-39307

CVE-2021-39307 is a medium-severity vulnerability in Pdftron Webviewer Ui with a CVSS 3.x base score of 6.1. 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: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Pdftron Webviewer Ui
Published: 2021-09-15
Last modified: 2026-06-17

Description

PDFTron's WebViewer UI 8.0 or below renders dangerous URLs as hyperlinks in supported documents, including JavaScript URLs, allowing the execution of arbitrary JavaScript code.

Frequently asked questions

What is CVE-2021-39307?: PDFTron's WebViewer UI 8.0 or below renders dangerous URLs as hyperlinks in supported documents, including JavaScript URLs, allowing the execution of arbitrary JavaScript code.
How severe is CVE-2021-39307?: CVE-2021-39307 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-39307 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39307?: CVE-2021-39307 affects Pdftron Webviewer Ui. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39307?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39307 published?: CVE-2021-39307 was published on 2021-09-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pdftron:webviewer_ui:*:*:*:*:*:*:*:*

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