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Vulnerability details: VCID-w5du-w6ad-dbcn
Vulnerability ID VCID-w5du-w6ad-dbcn
Aliases CVE-2021-29967
Summary Mozilla developers Gabriele Svelto, Anny Gakhokidze, Alexandru Michis, Christian Holler reported memory safety bugs present in Firefox 88 and Firefox ESR 78.10. 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 (2)
CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-787 Out-of-bounds Write
System Score Found at
cvssv3 8.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29967.json
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00175 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00182 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
epss 0.00183 https://api.first.org/data/v1/epss?cve=CVE-2021-29967
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-29967
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-29967
archlinux High https://security.archlinux.org/AVG-2018
archlinux High https://security.archlinux.org/AVG-2035
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-23
generic_textual none https://www.mozilla.org/en-US/security/advisories/mfsa2021-24
generic_textual none https://www.mozilla.org/en-US/security/advisories/mfsa2021-26
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29967.json
https://api.first.org/data/v1/epss?cve=CVE-2021-29967
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1602862%2C1703191%2C1703760%2C1704722%2C1706041
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29956
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29957
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29967
https://security.gentoo.org/glsa/202208-14
https://www.mozilla.org/security/advisories/mfsa2021-23/
https://www.mozilla.org/security/advisories/mfsa2021-24/
https://www.mozilla.org/security/advisories/mfsa2021-26/
1966831 https://bugzilla.redhat.com/show_bug.cgi?id=1966831
ASA-202106-22 https://security.archlinux.org/ASA-202106-22
ASA-202106-3 https://security.archlinux.org/ASA-202106-3
AVG-2018 https://security.archlinux.org/AVG-2018
AVG-2035 https://security.archlinux.org/AVG-2035
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:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
CVE-2021-29967 https://nvd.nist.gov/vuln/detail/CVE-2021-29967
mfsa2021-23 https://www.mozilla.org/en-US/security/advisories/mfsa2021-23
mfsa2021-24 https://www.mozilla.org/en-US/security/advisories/mfsa2021-24
mfsa2021-26 https://www.mozilla.org/en-US/security/advisories/mfsa2021-26
RHSA-2021:2206 https://access.redhat.com/errata/RHSA-2021:2206
RHSA-2021:2208 https://access.redhat.com/errata/RHSA-2021:2208
RHSA-2021:2214 https://access.redhat.com/errata/RHSA-2021:2214
RHSA-2021:2233 https://access.redhat.com/errata/RHSA-2021:2233
RHSA-2021:2261 https://access.redhat.com/errata/RHSA-2021:2261
RHSA-2021:2262 https://access.redhat.com/errata/RHSA-2021:2262
RHSA-2021:2263 https://access.redhat.com/errata/RHSA-2021:2263
RHSA-2021:2264 https://access.redhat.com/errata/RHSA-2021:2264
USN-4978-1 https://usn.ubuntu.com/4978-1/
USN-4995-1 https://usn.ubuntu.com/4995-1/
USN-4995-2 https://usn.ubuntu.com/4995-2/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29967.json
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:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-29967
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-2021-29967
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 0.39326
EPSS Score 0.00175
Published At Aug. 11, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:47.150611+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-24.yml 37.0.0