Is CVE-2021-43538 in the CISA KEV catalog?

No. CVE-2021-43538 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-43538?

CVE-2021-43538 has a CVSS v3 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2021-43538?

CVE-2021-43538 has an EPSS score of 1.16% (63th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-43538?

Upgrade firefox on debian unstable to 95.0-1 or later. Fixes are available for 7 affected products.

CVE & CISA-KEV Catalog

CVE-2021-43538

MEDIUM

4.3

CVSS v3

NVD

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.

CWE-362Race Condition

How to fix

Remediation Available

firefoxDebian

Fixed in:95.0-1CVE-2021-43538

firefoxUbuntu

Fixed in:95.0+build1-0ubuntu0.18.04.1USN-5186-1

Fixed in:95.0+build1-0ubuntu0.20.04.1USN-5186-1

thunderbirdUbuntu

Fixed in:1:91.5.0+build1-0ubuntu0.18.04.1USN-5248-1

Fixed in:1:91.5.0+build1-0ubuntu0.20.04.1USN-5248-1

DeveloperEditionWindows application

Affected:95.0Fixed in:95.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:95.0Fixed in:95.0Mozilla

Mozilla Firefox ESR (en-US)Windows application

Affected:91.4.0Fixed in:91.4.0Mozilla

Mozilla Thunderbird (en-US)Windows application

Affected:91.4.0Fixed in:91.4.0Mozilla

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Exploit Intelligence

1.16%probability of exploitation in 30 days

63rdpercentile

Moderate risk: more likely to be exploited than 63% of all known CVEs.

References

Vendor Advisory4

Third-Party Advisory6

Related Vulnerabilities

Other CWE-362 (Race Condition) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-6387	High	8.1	100%	-	Fix
CVE-2023-36884	High	7.5	99%	KEV + Ransom	Fix
CVE-2018-15473	Medium	5.3	99%	-	Fix
CVE-2024-27983	High	8.2	87%	-	Fix
CVE-2014-0226	Medium	6.8	86%	-	Fix
CVE-2016-5195	High	7.0	84%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.