Is CVE-2021-23971 in the CISA KEV catalog?

No. CVE-2021-23971 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-23971?

CVE-2021-23971 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2021-23971?

CVE-2021-23971 has an EPSS score of 1.01% (59th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-23971?

Upgrade firefox on debian unstable to 86.0-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-23971

MEDIUM

6.5

CVSS v3

NVD

Description

When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect's Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox < 86.

How to fix

Remediation Available

firefoxDebian

Fixed in:86.0-1CVE-2021-23971

firefoxUbuntu

Fixed in:86.0+build3-0ubuntu0.16.04.1USN-4756-1

Fixed in:86.0+build3-0ubuntu0.18.04.1USN-4756-1

Fixed in:86.0+build3-0ubuntu0.20.04.1USN-4756-1

DeveloperEditionWindows application

Affected:86.0Fixed in:86.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:86.0Fixed in:86.0Mozilla

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

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

1.01%probability of exploitation in 30 days

59thpercentile

Moderate risk: more likely to be exploited than 59% of all known CVEs.

References

Vendor Advisory2

Third-Party Advisory1

security.gentoo.org

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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.