Vulnerability in Mozilla Firefox

CVE-2018-18506

When proxy auto-detection is enabled, if a web server serves a Proxy Auto-Configuration (PAC) file or if a PAC file is loaded locally, this PAC file can specify that requests to the localhost are to be sent through the proxy to another server. This behavior is disallowed by default when a proxy is manually configured, but when enabled could allow for attacks on services and tools that bind to the localhost for networked behavior if they are accessed through browsing. This vulnerability affects Firefox < 65.

EPSS: 0.022 (80.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2018-18506?
CVE-2018-18506 is a medium-severity vulnerability in Mozilla Firefox. CVSS score: 5.9/10. Published 2019-02-05.
How severe is CVE-2018-18506?
Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2018-18506 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.