Search for vulnerabilities
Vulnerability details: VCID-2d29-3cre-5bh8
Vulnerability ID VCID-2d29-3cre-5bh8
Aliases CVE-2021-38500
Summary Mozilla developers and community members Andreas Pehrson and Christian Holler reported memory safety bugs present in Thunderbird 91.1. 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-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
System Score Found at
cvssv3 8.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38500.json
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
epss 0.01635 https://api.first.org/data/v1/epss?cve=CVE-2021-38500
cvssv2 6.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38500
cvssv3.1 8.8 https://nvd.nist.gov/vuln/detail/CVE-2021-38500
archlinux High https://security.archlinux.org/AVG-2443
archlinux High https://security.archlinux.org/AVG-2459
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-43
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-44
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-45
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-47
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38500.json
https://api.first.org/data/v1/epss?cve=CVE-2021-38500
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1725854%2C1728321
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38496
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38500
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38502
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38503
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38504
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38506
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38507
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38508
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38509
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4126
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4129
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43528
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43529
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43534
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43535
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43536
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43537
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43538
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43539
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43541
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43542
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43543
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43545
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43546
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44538
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
https://www.debian.org/security/2022/dsa-5034
https://www.mozilla.org/security/advisories/mfsa2021-43/
https://www.mozilla.org/security/advisories/mfsa2021-44/
https://www.mozilla.org/security/advisories/mfsa2021-45/
https://www.mozilla.org/security/advisories/mfsa2021-46/
https://www.mozilla.org/security/advisories/mfsa2021-47/
2011100 https://bugzilla.redhat.com/show_bug.cgi?id=2011100
AVG-2443 https://security.archlinux.org/AVG-2443
AVG-2459 https://security.archlinux.org/AVG-2459
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:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
CVE-2021-38500 https://nvd.nist.gov/vuln/detail/CVE-2021-38500
mfsa2021-43 https://www.mozilla.org/en-US/security/advisories/mfsa2021-43
mfsa2021-44 https://www.mozilla.org/en-US/security/advisories/mfsa2021-44
mfsa2021-45 https://www.mozilla.org/en-US/security/advisories/mfsa2021-45
mfsa2021-47 https://www.mozilla.org/en-US/security/advisories/mfsa2021-47
RHSA-2021:3755 https://access.redhat.com/errata/RHSA-2021:3755
RHSA-2021:3756 https://access.redhat.com/errata/RHSA-2021:3756
RHSA-2021:3757 https://access.redhat.com/errata/RHSA-2021:3757
RHSA-2021:3791 https://access.redhat.com/errata/RHSA-2021:3791
RHSA-2021:3838 https://access.redhat.com/errata/RHSA-2021:3838
RHSA-2021:3839 https://access.redhat.com/errata/RHSA-2021:3839
RHSA-2021:3840 https://access.redhat.com/errata/RHSA-2021:3840
RHSA-2021:3841 https://access.redhat.com/errata/RHSA-2021:3841
USN-5107-1 https://usn.ubuntu.com/5107-1/
USN-5132-1 https://usn.ubuntu.com/5132-1/
USN-5248-1 https://usn.ubuntu.com/5248-1/
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://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38500.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-2021-38500
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-2021-38500
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 0.8115
EPSS Score 0.01635
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:46.564596+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-47.yml 37.0.0