CVE-2021-38506
MEDIUM
4.3
CVSS Score
Published: December 8, 2021 at 09:21 PM UTC
Updated: June 17, 2026 at 04:02 AM UTC
4 products affected across 2 vendorsDebian LinuxFirefoxThunderbird
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Severity
MEDIUM4.3
Exploit prediction
EPSS 2%
Description
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.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Debian Linux· Debiandrupal
95%v < 94
Affected range stops below 94, so it looks safe — our inference, not a vendor statement
Affected range stops below 94.0, so it looks safe — our inference, not a vendor statement
v < 91.3
Affected range stops below 91.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 91.3.0, so it looks safe — our inference, not a vendor statement
v < 91.3
Affected range stops below 91.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 91.3.0, so it looks safe — our inference, not a vendor statement
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
References (10)
x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=1730750Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlVendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202202-03Vendor Advisoryx_refsource_GENTOOThird Party Advisory
Source: [email protected]
https://security.gentoo.org/glsa/202208-14Vendor Advisoryx_refsource_DEBIANThird Party Advisory
Source: [email protected]
https://www.debian.org/security/2021/dsa-5026Vendor Advisoryx_refsource_DEBIANThird Party Advisory
Source: [email protected]
https://www.debian.org/security/2022/dsa-5034x_refsource_MISCVendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2021-48/CVSS
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- REQUIRED
- Scope
- UNCHANGED
- Confidentiality
- NONE
- Integrity
- LOW
- Availability
- NONE
Vector?
Quick Info
StatusMODIFIED
CWE
CWE-1021
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