How severe is CVE-2019-11720?

CVE-2019-11720 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-2019-11720 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-2019-11720?

CVE-2019-11720 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-11720?

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

When was CVE-2019-11720 published?

CVE-2019-11720 was published on 2019-07-23 and last updated on 2026-06-17.

CVE-2019-11720

CVE-2019-11720 is a medium-severity vulnerability in Mozilla Firefox 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: Mozilla Firefox
Published: 2019-07-23
Last modified: 2026-06-17

Description

Some unicode characters are incorrectly treated as whitespace during the parsing of web content instead of triggering parsing errors. This allows malicious code to then be processed, evading cross-site scripting (XSS) filtering. This vulnerability affects Firefox < 68.

Frequently asked questions

What is CVE-2019-11720?: Some unicode characters are incorrectly treated as whitespace during the parsing of web content instead of triggering parsing errors. This allows malicious code to then be processed, evading cross-site scripting (XSS) filtering. This vulnerability affects Firefox < 68.
How severe is CVE-2019-11720?: CVE-2019-11720 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-2019-11720 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-2019-11720?: CVE-2019-11720 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-11720?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-11720 published?: CVE-2019-11720 was published on 2019-07-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

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