CVE-2021-43538
MEDIUM
4.3
CVSS Score
Published: December 8, 2021 at 09:20 PM UTC
Updated: June 17, 2026 at 04:11 AM UTC
4 products affected across 2 vendorsDebian LinuxFirefoxThunderbird
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Severity
MEDIUM4.3
Exploit prediction
EPSS 1%
Description
By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Debian Linux· Debiandrupal
95%v < 95
Affected range stops below 95, so it looks safe — our inference, not a vendor statement
Affected range stops below 95.0, so it looks safe — our inference, not a vendor statement
v < 91.4.0
Affected range stops below 91.4.0, so it looks safe — our inference, not a vendor statement
v < 91.4.0
Affected range stops below 91.4.0, 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=1739091Mailing 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/mfsa2021-52/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-362
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