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Fencer Vulns
medium 6.1

CVE-2023-34415 json

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 doc…

published 2023-06-19 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-38492

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

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.

Patch / fix

  • Mozilla Firefox 114
  • firefox Ubuntu 20.04 LTS 114.0+build3-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-34415

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 114.0.1-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:12991-1

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

  • Mozilla Firefox

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.