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Vulnerability details: VCID-cxyq-my35-jfh6
Vulnerability ID VCID-cxyq-my35-jfh6
Aliases CVE-2021-38495
Summary Mozilla developers Tyson Smith, Christian Holler, and Gabriele Svelto reported memory safety bugs present in Thunderbird 78.13.0. 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 7.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38495.json
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00284 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00298 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00298 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00298 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00298 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.00298 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
epss 0.0044 https://api.first.org/data/v1/epss?cve=CVE-2021-38495
cvssv3.1 7.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38495
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38495
archlinux High https://security.archlinux.org/AVG-2291
generic_textual low https://www.mozilla.org/en-US/security/advisories/mfsa2021-40
generic_textual low https://www.mozilla.org/en-US/security/advisories/mfsa2021-41
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38495.json
https://api.first.org/data/v1/epss?cve=CVE-2021-38495
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1723391%2C1723920%2C1724101%2C1724107
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://security.gentoo.org/glsa/202202-03
https://security.gentoo.org/glsa/202208-14
https://www.mozilla.org/security/advisories/mfsa2021-40/
https://www.mozilla.org/security/advisories/mfsa2021-41/
2002900 https://bugzilla.redhat.com/show_bug.cgi?id=2002900
AVG-2291 https://security.archlinux.org/AVG-2291
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-2021-38495 https://nvd.nist.gov/vuln/detail/CVE-2021-38495
mfsa2021-40 https://www.mozilla.org/en-US/security/advisories/mfsa2021-40
mfsa2021-41 https://www.mozilla.org/en-US/security/advisories/mfsa2021-41
USN-5248-1 https://usn.ubuntu.com/5248-1/
No exploits are available.
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38495.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: CVSS:3.1/AV:N/AC:H/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
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-38495
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-2021-38495
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 0.51432
EPSS Score 0.00284
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:47.286517+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-41.yml 37.0.0