How severe is CVE-2015-4490?

CVE-2015-4490 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2015-4490 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-4490?

CVE-2015-4490 primarily affects Mozilla Firefox. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-4490?

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

When was CVE-2015-4490 published?

CVE-2015-4490 was published on 2015-08-16 and last updated on 2026-06-17.

CVE-2015-4490

CVE-2015-4490 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 4.3. 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 2.0 base score 4.3)
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mozilla Firefox
Published: 2015-08-16
Last modified: 2026-06-17

Description

The nsCSPHostSrc::permits function in dom/security/nsCSPUtils.cpp in Mozilla Firefox before 40.0 does not implement the Content Security Policy Level 2 exceptions for the blob, data, and filesystem URL schemes during wildcard source-expression matching, which might make it easier for remote attackers to conduct cross-site scripting (XSS) attacks by leveraging unexpected policy-enforcement behavior.

Frequently asked questions

What is CVE-2015-4490?: The nsCSPHostSrc::permits function in dom/security/nsCSPUtils.cpp in Mozilla Firefox before 40.0 does not implement the Content Security Policy Level 2 exceptions for the blob, data, and filesystem URL schemes during wildcard source-expression matching, which might make it easier for remote attackers to conduct cross-site scripting (XSS) attacks by leveraging unexpected policy-enforcement behavior.
How severe is CVE-2015-4490?: CVE-2015-4490 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2015-4490 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-4490?: CVE-2015-4490 primarily affects Mozilla Firefox. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-4490?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-4490 published?: CVE-2015-4490 was published on 2015-08-16 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:15.04:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
cpe:2.3:o:oracle:solaris:11.3:*:*:*:*:*:*:*

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