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Vulnerability details: VCID-35jx-ns8x-zuet
Vulnerability ID VCID-35jx-ns8x-zuet
Aliases CVE-2021-29969
Summary If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server responses prior to the completion of the STARTTLS handshake, then Thunderbird didn't ignore the injected data. This could have resulted in Thunderbird showing incorrect information, for example the attacker could have tricked Thunderbird to show folders that didn't exist on the IMAP server.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-345 Insufficient Verification of Data Authenticity
CWE-552 Files or Directories Accessible to External Parties
System Score Found at
cvssv3 5.9 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29969.json
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00155 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00396 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00398 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00398 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00398 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00398 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
epss 0.00398 https://api.first.org/data/v1/epss?cve=CVE-2021-29969
cvssv3.1 7.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-29969
cvssv3.1 5.9 https://nvd.nist.gov/vuln/detail/CVE-2021-29969
archlinux High https://security.archlinux.org/AVG-2152
generic_textual high https://www.mozilla.org/en-US/security/advisories/mfsa2021-30
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29969.json
https://api.first.org/data/v1/epss?cve=CVE-2021-29969
https://bugzilla.mozilla.org/show_bug.cgi?id=1682370
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29969
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29970
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29976
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-30547
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://security.gentoo.org/glsa/202208-14
https://www.mozilla.org/security/advisories/mfsa2021-30/
1982015 https://bugzilla.redhat.com/show_bug.cgi?id=1982015
ASA-202107-21 https://security.archlinux.org/ASA-202107-21
AVG-2152 https://security.archlinux.org/AVG-2152
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-2021-29969 https://nvd.nist.gov/vuln/detail/CVE-2021-29969
mfsa2021-30 https://www.mozilla.org/en-US/security/advisories/mfsa2021-30
RHSA-2021:2881 https://access.redhat.com/errata/RHSA-2021:2881
RHSA-2021:2882 https://access.redhat.com/errata/RHSA-2021:2882
RHSA-2021:2883 https://access.redhat.com/errata/RHSA-2021:2883
RHSA-2021:2914 https://access.redhat.com/errata/RHSA-2021:2914
USN-5058-1 https://usn.ubuntu.com/5058-1/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-29969.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:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-29969
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:H/PR:N/UI:N/S:U/C:H/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-29969
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 0.37054
EPSS Score 0.00155
Published At July 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:09:48.633679+00:00 Mozilla Importer Import https://github.com/mozilla/foundation-security-advisories/blob/master/announce/2021/mfsa2021-30.yml 37.0.0