How severe is CVE-2018-5108?

CVE-2018-5108 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2018-5108 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-5108?

CVE-2018-5108 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-5108?

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

When was CVE-2018-5108 published?

CVE-2018-5108 was published on 2018-06-11 and last updated on 2026-06-17.

CVE-2018-5108

CVE-2018-5108 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Mozilla Firefox
Published: 2018-06-11
Last modified: 2026-06-17

Description

A Blob URL can violate origin attribute segregation, allowing it to be accessed from a private browsing tab and for data to be passed between the private browsing tab and a normal tab. This could allow for the leaking of private information specific to the private browsing context. This issue is mitigated by the requirement that the user enter the Blob URL manually in order for the access violation to occur. This vulnerability affects Firefox < 58.

Frequently asked questions

What is CVE-2018-5108?: A Blob URL can violate origin attribute segregation, allowing it to be accessed from a private browsing tab and for data to be passed between the private browsing tab and a normal tab. This could allow for the leaking of private information specific to the private browsing context. This issue is mitigated by the requirement that the user enter the Blob URL manually in order for the access violation to occur. This vulnerability affects Firefox < 58.
How severe is CVE-2018-5108?: CVE-2018-5108 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2018-5108 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-5108?: CVE-2018-5108 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-5108?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-5108 published?: CVE-2018-5108 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (4)

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:*:*:*:*:*:*:*

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