CVE-2021-39307

MEDIUMNVD 6.16.1—

6.1

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.

CVSS v3: 6.1
EG Score: 6.1(medium)
EPSS: 68.8%
KEV: Not listed

Published

September 15, 2021

Last Modified

November 21, 2024

References (4)

cve@mitrehttps://research.nccgroup.com/2021/09/14/technical-advisory-pdftron-javascript-urls-allowed-in-webviewer-ui-cve-2021-39307/
cve@mitrehttps://www.pdftron.com/webviewer/
af854a3a-2127-422b-91ae-364da2661108https://research.nccgroup.com/2021/09/14/technical-advisory-pdftron-javascript-urls-allowed-in-webviewer-ui-cve-2021-39307/
af854a3a-2127-422b-91ae-364da2661108https://www.pdftron.com/webviewer/

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-79Cross-site Scripting (XSS)

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-39307?

CVE-2021-39307 is a medium vulnerability published on September 15, 2021. 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.

When was CVE-2021-39307 disclosed?

CVE-2021-39307 was first published in the National Vulnerability Database on September 15, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-39307 actively exploited?

CVE-2021-39307 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 68.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-39307?

CVE-2021-39307 has a CVSS v3 base score of 6.1 (NVD).

How do I remediate CVE-2021-39307?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-39307, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-39307

📅 Published

🔄 Last Modified

🔗 References (4)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-39307?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (4)

Frequently asked(5)

Related CVEs(same CWE)