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Vulnerability details: VCID-5db7-f394-tbee
Vulnerability ID VCID-5db7-f394-tbee
Aliases CVE-2021-23957
Summary Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe sandbox.*Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*
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 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
epss 0.00286 https://api.first.org/data/v1/epss?cve=CVE-2021-23957
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-23957
cvssv3.1 7.4 https://nvd.nist.gov/vuln/detail/CVE-2021-23957
archlinux Medium https://security.archlinux.org/AVG-1493
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-03
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-23957
https://bugzilla.mozilla.org/show_bug.cgi?id=1584582
https://www.mozilla.org/security/advisories/mfsa2021-03/
AVG-1493 https://security.archlinux.org/AVG-1493
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:android:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:firefox:*:*:*:*:*:android:*:*
CVE-2021-23957 https://nvd.nist.gov/vuln/detail/CVE-2021-23957
mfsa2021-03 https://www.mozilla.org/en-US/security/advisories/mfsa2021-03
No exploits are available.
Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23957
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:C/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23957
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 0.51746
EPSS Score 0.00286
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:50.382037+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-03.yml 37.0.0