How severe is CVE-2018-5164?

CVE-2018-5164 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-2018-5164 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-5164?

CVE-2018-5164 primarily affects Mozilla Firefox. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-5164?

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

When was CVE-2018-5164 published?

CVE-2018-5164 was published on 2018-06-11 and last updated on 2026-06-17.

CVE-2018-5164

CVE-2018-5164 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: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mozilla Firefox
Published: 2018-06-11
Last modified: 2026-06-17

Description

Content Security Policy (CSP) is not applied correctly to all parts of multipart content sent with the "multipart/x-mixed-replace" MIME type. This could allow for script to run where CSP should block it, allowing for cross-site scripting (XSS) and other attacks. This vulnerability affects Firefox < 60.

Frequently asked questions

What is CVE-2018-5164?: Content Security Policy (CSP) is not applied correctly to all parts of multipart content sent with the "multipart/x-mixed-replace" MIME type. This could allow for script to run where CSP should block it, allowing for cross-site scripting (XSS) and other attacks. This vulnerability affects Firefox < 60.
How severe is CVE-2018-5164?: CVE-2018-5164 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-2018-5164 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-5164?: CVE-2018-5164 primarily affects Mozilla Firefox. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-5164?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-5164 published?: CVE-2018-5164 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

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