CVE-2023-34415

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-19 · updated 2026-06-17
Weakness: CWE-601

Description

When choosing a site-isolated process for a document loaded from a data: URL that was the result of a redirect, Firefox would load that document in the same process as the site that issued the redirect. This bypassed the site-isolation protections against Spectre-like attacks on sites that host an "open redirect". Firefox no longer follows HTTP redirects to data: URLs. This vulnerability affects Firefox < 114.

Affected products

Mozilla Firefox: before 114.0 — fixed in 114.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 114.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1811999
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-20/
https://bugzilla.mozilla.org/show_bug.cgi?id=1811999
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-20/

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