Search for vulnerabilities
Vulnerability details: VCID-6h36-r9kp-aaah
Vulnerability ID VCID-6h36-r9kp-aaah
Aliases CVE-2021-23993
Summary An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-347 Improper Verification of Cryptographic Signature
CWE-327 Use of a Broken or Risky Cryptographic Algorithm
System Score Found at
generic_textual Medium http://people.canonical.com/~ubuntu-security/cve/2021/CVE-2021-23993.html
rhas Moderate https://access.redhat.com/errata/RHSA-2021:1190
rhas Moderate https://access.redhat.com/errata/RHSA-2021:1192
rhas Moderate https://access.redhat.com/errata/RHSA-2021:1193
rhas Moderate https://access.redhat.com/errata/RHSA-2021:1201
cvssv3 6.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-23993.json
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00073 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
epss 0.00076 https://api.first.org/data/v1/epss?cve=CVE-2021-23993
rhbs medium https://bugzilla.redhat.com/show_bug.cgi?id=1948395
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23961
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23991
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23992
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23993
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23994
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23995
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23998
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23999
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-24002
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29945
generic_textual Medium https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29946
generic_textual Low https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29948
generic_textual Low https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29949
cvssv3.1 4.3 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-23993
cvssv3 6.5 https://nvd.nist.gov/vuln/detail/CVE-2021-23993
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2021-23993
archlinux Medium https://security.archlinux.org/AVG-1790
generic_textual Medium https://ubuntu.com/security/notices/USN-4995-1
generic_textual Medium https://ubuntu.com/security/notices/USN-4995-2
generic_textual none https://www.mozilla.org/en-US/security/advisories/mfsa2021-13
generic_textual Medium https://www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993
Reference id Reference type URL
http://people.canonical.com/~ubuntu-security/cve/2021/CVE-2021-23993.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-23993.json
https://api.first.org/data/v1/epss?cve=CVE-2021-23993
https://bugzilla.mozilla.org/show_bug.cgi?id=1666360
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23961
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23991
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23992
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23993
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23994
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23995
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23998
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23999
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-24002
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29945
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29946
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29948
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29949
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://ubuntu.com/security/notices/USN-4995-1
https://ubuntu.com/security/notices/USN-4995-2
https://www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993
https://www.mozilla.org/security/advisories/mfsa2021-13/
1948395 https://bugzilla.redhat.com/show_bug.cgi?id=1948395
AVG-1790 https://security.archlinux.org/AVG-1790
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-2021-23993 https://nvd.nist.gov/vuln/detail/CVE-2021-23993
mfsa2021-13 https://www.mozilla.org/en-US/security/advisories/mfsa2021-13
RHSA-2021:1190 https://access.redhat.com/errata/RHSA-2021:1190
RHSA-2021:1192 https://access.redhat.com/errata/RHSA-2021:1192
RHSA-2021:1193 https://access.redhat.com/errata/RHSA-2021:1193
RHSA-2021:1201 https://access.redhat.com/errata/RHSA-2021:1201
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:N/I:H/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-23993.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:L/PR:N/UI:R/S:U/C:N/I:N/A:L 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:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23993
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:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23993
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:L/PR:N/UI:R/S:U/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-23993
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 0.1389
EPSS Score 0.00054
Published At March 28, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
There are no relevant records.