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Vulnerability details: VCID-y524-aq48-aaaa
Vulnerability ID VCID-y524-aq48-aaaa
Aliases CVE-2021-40823
GHSA-23cm-x6j7-6hq3
Summary A logic error in the room key sharing functionality of matrix-js-sdk (aka Matrix Javascript SDK) before 12.4.1 allows a malicious Matrix homeserver present in an encrypted room to steal room encryption keys (via crafted Matrix protocol messages) that were originally sent by affected Matrix clients participating in that room. This allows the homeserver to decrypt end-to-end encrypted messages sent by affected clients.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (5)
CWE-290 Authentication Bypass by Spoofing
CWE-327 Use of a Broken or Risky Cryptographic Algorithm
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00084 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00085 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00085 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00085 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00085 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00261 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
epss 0.00547 https://api.first.org/data/v1/epss?cve=CVE-2021-40823
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-23cm-x6j7-6hq3
cvssv3.1 4.1 https://github.com/matrix-org/matrix-js-sdk
generic_textual HIGH https://github.com/matrix-org/matrix-js-sdk
cvssv3.1 5.9 https://github.com/matrix-org/matrix-js-sdk/commit/894c24880da0e1cc81818f51c0db80e3c9fb2be9
generic_textual MODERATE https://github.com/matrix-org/matrix-js-sdk/commit/894c24880da0e1cc81818f51c0db80e3c9fb2be9
cvssv3.1 5.9 https://github.com/matrix-org/matrix-js-sdk/releases/tag/v12.4.1
generic_textual MODERATE https://github.com/matrix-org/matrix-js-sdk/releases/tag/v12.4.1
cvssv3.1_qr MODERATE https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-23cm-x6j7-6hq3
cvssv3.1 5.9 https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing
generic_textual MODERATE https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2021-40823
cvssv3 5.9 https://nvd.nist.gov/vuln/detail/CVE-2021-40823
cvssv3.1 5.9 https://nvd.nist.gov/vuln/detail/CVE-2021-40823
archlinux High https://security.archlinux.org/AVG-2377
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-40823
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-40823
https://github.com/matrix-org/matrix-js-sdk
https://github.com/matrix-org/matrix-js-sdk/commit/894c24880da0e1cc81818f51c0db80e3c9fb2be9
https://github.com/matrix-org/matrix-js-sdk/releases/tag/v12.4.1
https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing
866502 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=866502
ASA-202109-4 https://security.archlinux.org/ASA-202109-4
ASA-202109-5 https://security.archlinux.org/ASA-202109-5
AVG-2377 https://security.archlinux.org/AVG-2377
cpe:2.3:a:matrix:javascript_sdk:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:matrix:javascript_sdk:*:*:*:*:*:*:*:*
CVE-2021-40823 https://nvd.nist.gov/vuln/detail/CVE-2021-40823
GHSA-23cm-x6j7-6hq3 https://github.com/advisories/GHSA-23cm-x6j7-6hq3
GHSA-23cm-x6j7-6hq3 https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-23cm-x6j7-6hq3
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:L Found at https://github.com/matrix-org/matrix-js-sdk
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:N/S:U/C:H/I:N/A:N Found at https://github.com/matrix-org/matrix-js-sdk/commit/894c24880da0e1cc81818f51c0db80e3c9fb2be9
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:N/S:U/C:H/I:N/A:N Found at https://github.com/matrix-org/matrix-js-sdk/releases/tag/v12.4.1
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:N/S:U/C:H/I:N/A:N Found at https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing
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-2021-40823
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-2021-40823
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:N/S:U/C:H/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-40823
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 0.36837
EPSS Score 0.00084
Published At Nov. 1, 2024, midnight
Date Actor Action Source VulnerableCode Version
There are no relevant records.