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,…

Description

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.

Scores

EPSS (exploitation in 30 days)

2.2% · top 17% of all CVEs (6 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

• Proxy Auto-Configuration file can define localhost access to be proxied

Affected products

• Mozilla · Firefox

  • affected unspecified – < 65

References (21)

• https://www.mozilla.org/security/advisories/mfsa2019-01/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• 106773 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
• USN-3874-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• RHSA-2019:0623 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:0622 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• 20190320 [SECURITY] [DSA 4411-1] firefox-esr security update (opens in a new tab)mailing-listx_refsource_BUGTRAQx_transferred
• DSA-4411 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• [debian-lts-announce] 20190321 [SECURITY] [DLA 1722-1] firefox-esr security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• openSUSE-SU-2019:1056 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• RHSA-2019:0680 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:0681 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• USN-3927-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
• openSUSE-SU-2019:1077 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• DSA-4420 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• 20190401 [SECURITY] [DSA 4420-1] thunderbird security update (opens in a new tab)mailing-listx_refsource_BUGTRAQx_transferred
• [debian-lts-announce] 20190401 [SECURITY] [DLA 1743-1] thunderbird security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• GLSA-201904-07 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
• openSUSE-SU-2019:1126 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• openSUSE-SU-2019:1162 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• RHSA-2019:0966 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2019:1144 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2018-18506](https://trackcve.app/badge/CVE-2018-18506.svg)](https://trackcve.app/cve/CVE-2018-18506)

Record last updated 5 Aug 2024, 11:08 UTC.