CVE-2017-5384
Proxy Auto-Config (PAC) files can specify a JavaScript function called for all URL requests with the full URL path which exposes more information than would be sent to the proxy itself in the case of HTTPS.
Does this matter?
Lower severity and a low EPSS score (1.47%). Track it; it rarely justifies an emergency change on its own.
Description
Proxy Auto-Config (PAC) files can specify a JavaScript function called for all URL requests with the full URL path which exposes more information than would be sent to the proxy itself in the case of HTTPS. Normally the Proxy Auto-Config file is specified by the user or machine owner and presumed to be non-malicious, but if a user has enabled Web Proxy Auto Detect (WPAD) this file can be served remotely. This vulnerability affects Firefox < 51.
- CVSS 3.0
- 5.9 MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 1.47% probability · 74th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-200
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 1.5% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/95763Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037693Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1255474Issue Tracking, Patch, Vendor Advisory
- https://www.contextis.com//resources/blog/leaking-https-urls-20-year-old-vulnerability/Exploit, Technical Description, Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-01/Vendor Advisory
- http://www.securityfocus.com/bid/95763Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037693Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1255474Issue Tracking, Patch, Vendor Advisory
- https://www.contextis.com//resources/blog/leaking-https-urls-20-year-old-vulnerability/Exploit, Technical Description, Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2017-01/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.