CVE-2018-12403 — If a site is loaded over a HTTPS connection but loads a favicon resource over HT

If a site is loaded over a HTTPS connection but loads a favicon resource over HTTP, the mixed content warning is not displayed to users. This vulnerability affects Firefox < 63.

01What is this vulnerability?

If a site is loaded over a HTTPS connection but loads a favicon resource over HTTP, the mixed content warning is not displayed to users. This vulnerability affects Firefox < 63.

02Affected products

Vendor	Product	Versions
Mozilla	Firefox	unspecified

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-02-28T18:00:00.000Z
• Last modified: 2024-08-05T08:38:04.796Z

09References

• www.mozilla.org — https://www.mozilla.org/security/advisories/mfsa2018-26/
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1484753
• www.securityfocus.com — http://www.securityfocus.com/bid/105721
• usn.ubuntu.com — https://usn.ubuntu.com/3801-1/
• www.securitytracker.com — http://www.securitytracker.com/id/1041944