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Vulnerability details: VCID-39ee-q1ke-87bd
Vulnerability ID VCID-39ee-q1ke-87bd
Aliases CVE-2021-38499
Summary Mozilla developers and community members Julien Cristau, Christian Holler reported memory safety bugs present in Firefox 92. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-787 Out-of-bounds Write
System Score Found at
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
epss 0.0042 https://api.first.org/data/v1/epss?cve=CVE-2021-38499
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38499
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38499
archlinux High https://security.archlinux.org/AVG-2443
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-43
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-38499
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1667102%2C1723170%2C1725356%2C1727364
https://www.mozilla.org/security/advisories/mfsa2021-43/
AVG-2443 https://security.archlinux.org/AVG-2443
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-2021-38499 https://nvd.nist.gov/vuln/detail/CVE-2021-38499
mfsa2021-43 https://www.mozilla.org/en-US/security/advisories/mfsa2021-43
USN-5107-1 https://usn.ubuntu.com/5107-1/
No exploits are available.
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-38499
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:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-38499
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 0.61093
EPSS Score 0.0042
Published At Aug. 7, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:50.174144+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-43.yml 37.0.0