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Vulnerability details: VCID-ebus-cbbm-u3dn
Vulnerability ID VCID-ebus-cbbm-u3dn
Aliases CVE-2021-29947
Summary Mozilla developers and community members Ryan VanderMeulen, Sean Feng, Tyson Smith, Julian Seward, Christian Holler reported memory safety bugs present in Firefox 87. 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 (0)
There are no known CWE.
System Score Found at
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
epss 0.00348 https://api.first.org/data/v1/epss?cve=CVE-2021-29947
cvssv3.1 8.8 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
archlinux High https://security.archlinux.org/AVG-1834
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-16
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-29947
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
ASA-202104-3 https://security.archlinux.org/ASA-202104-3
AVG-1834 https://security.archlinux.org/AVG-1834
mfsa2021-16 https://www.mozilla.org/en-US/security/advisories/mfsa2021-16
USN-4926-1 https://usn.ubuntu.com/4926-1/
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://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
Exploit Prediction Scoring System (EPSS)
Percentile 0.57236
EPSS Score 0.00348
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T13:17:09.822798+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-16.yml 38.0.0