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Vulnerability details: VCID-esrg-38k2-5qbk
Vulnerability ID VCID-esrg-38k2-5qbk
Aliases CVE-2021-23971
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (0)
There are no known CWE.
System Score Found at
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
epss 0.00481 https://api.first.org/data/v1/epss?cve=CVE-2021-23971
cvssv3.1 6.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-23971
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2021-23971
archlinux High https://security.archlinux.org/AVG-1599
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-07
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-23971
https://bugzilla.mozilla.org/show_bug.cgi?id=1678545
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://security.gentoo.org/glsa/202104-10
https://www.mozilla.org/security/advisories/mfsa2021-07/
AVG-1599 https://security.archlinux.org/AVG-1599
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
CVE-2021-23971 https://nvd.nist.gov/vuln/detail/CVE-2021-23971
mfsa2021-07 https://www.mozilla.org/en-US/security/advisories/mfsa2021-07
USN-4756-1 https://usn.ubuntu.com/4756-1/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23971
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23971
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.64129
EPSS Score 0.00481
Published At Aug. 8, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:48.786794+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-07.yml 37.0.0