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CVE

CVE-2021-38506

Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user.

Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

MEDIUM · CVSS 4.3 EPSS 0.00865
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-1021Improper Restriction of Rendered UI Layers or Frames
▤

Affected Products & Versions

4
mozilla firefox< 94.0
mozilla firefox esr< 91.3.0
mozilla thunderbird< 91.3.0
debian linuxall versions
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSQLite Firefox Profile Data DB Access
▣

Scoring & Timeline

4.3
MEDIUM · CVSS v3.1 · security@mozilla.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD08 Dec 2021 · 10:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
⚑

Vendor Advisories

22
suse-csafopenSUSE-SU-2024:14572-1
suse-csafopenSUSE-SU-2024:11607-1
suse-csafopenSUSE-SU-2024:11614-1
usnUSN-5248-1
suse-csafopenSUSE-SU-2021:1635-1
🔗

References & Sources

10
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://bugzilla.mozilla.org/show_bug.cgi?id=1730750Issue TrackingPermissions RequiredVendor Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing ListThird Party Advisory
https://security.gentoo.org/glsa/202202-03Third Party Advisory
https://security.gentoo.org/glsa/202208-14Third Party Advisory
https://www.debian.org/security/2021/dsa-5026Third Party Advisory
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