CVE-2017-5391

CVE-2017-5391 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

Special "about:" pages used by web content, such as RSS feeds, can load privileged "about:" pages in an iframe. If a content-injection bug were found in one of those pages this could allow for potential privilege escalation. This vulnerability affects Firefox < 51.

Frequently asked questions

What is CVE-2017-5391?
Special "about:" pages used by web content, such as RSS feeds, can load privileged "about:" pages in an iframe. If a content-injection bug were found in one of those pages this could allow for potential privilege escalation. This vulnerability affects Firefox < 51.
How severe is CVE-2017-5391?
CVE-2017-5391 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-5391 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-5391?
CVE-2017-5391 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-5391?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-5391 published?
CVE-2017-5391 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (1)

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