What’s Vulnerable › Vulnerabilities

CVE-2018-5131

• Severity: medium (CVSS 5.9 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-06-11 · updated 2026-06-17
• Weakness: CWE-200

Description

Under certain circumstances the "fetch()" API can return transient local copies of resources that were sent with a "no-store" or "no-cache" cache header instead of downloading a copy from the network as it should. This can result in previously stored, locally cached data of a website being accessible to users if they share a common profile while browsing. This vulnerability affects Firefox ESR < 52.7 and Firefox < 59.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 17.10
• Debian Linux: 7.0, 8.0, 9.0
• Mozilla Firefox: before 59.0; before 52.7.0 — fixed in 52.7.0, 59.0
• RedHat Enterprise Linux Desktop: 6.0, 7.0
• RedHat Enterprise Linux Server: 6.0, 7.0
• RedHat Enterprise Linux Server Aus: 7.4
• RedHat Enterprise Linux Server Eus: 7.4, 7.5
• RedHat Enterprise Linux Workstation: 6.0, 7.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 52.7.0, 59.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/103388
• http://www.securitytracker.com/id/1040514
• https://access.redhat.com/errata/RHSA-2018:0526
• https://access.redhat.com/errata/RHSA-2018:0527
• https://bugzilla.mozilla.org/show_bug.cgi?id=1440775
• https://lists.debian.org/debian-lts-announce/2018/03/msg00010.html
• https://security.gentoo.org/glsa/201810-01
• https://usn.ubuntu.com/3596-1/
• https://www.debian.org/security/2018/dsa-4139
• https://www.mozilla.org/security/advisories/mfsa2018-06/
• https://www.mozilla.org/security/advisories/mfsa2018-07/
• http://www.securityfocus.com/bid/103388

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