What’s Vulnerable › Vulnerabilities

CVE-2017-7823

• Severity: medium (CVSS 5.4 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2018-06-11 · updated 2026-06-17
• Weakness: CWE-79

Description

The content security policy (CSP) "sandbox" directive did not create a unique origin for the document, causing it to behave as if the "allow-same-origin" keyword were always specified. This could allow a Cross-Site Scripting (XSS) attack to be launched from unsafe content. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

Affected products

• Debian Linux: 7.0, 8.0, 9.0
• Mozilla Firefox: before 52.4.0; before 56.0 — fixed in 52.4.0, 56.0
• Mozilla Thunderbird: before 52.4.0 — fixed in 52.4.0
• 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 52.4.0, 56.0; Mozilla Thunderbird 52.4.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/101059
• http://www.securitytracker.com/id/1039465
• https://access.redhat.com/errata/RHSA-2017:2831
• https://access.redhat.com/errata/RHSA-2017:2885
• https://bugzilla.mozilla.org/show_bug.cgi?id=1396320
• https://lists.debian.org/debian-lts-announce/2017/11/msg00000.html
• https://security.gentoo.org/glsa/201803-14
• https://www.debian.org/security/2017/dsa-3987
• https://www.debian.org/security/2017/dsa-4014
• https://www.mozilla.org/security/advisories/mfsa2017-21/
• https://www.mozilla.org/security/advisories/mfsa2017-22/
• https://www.mozilla.org/security/advisories/mfsa2017-23/

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