Auth bypass in Matrix JavaScript Sdk
CVE-2022-39251
Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver can construct messages that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. Starting with version 19.7.0, matrix-js-sdk has been modified to only accept Olm-encrypted to-device messages. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.012 (66.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.012 · change: +0.002
Affected products
- Matrix JavaScript Sdk
- Matrix-Org Matrix-Js-Sdk — versions < 19.7.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/matrix-org/matrix-js-sdk/commit/a587d7c36026fe1fcf93dfff63588abee359… (Patch, Third Party Advisory)
- github.com/matrix-org/matrix-js-sdk/releases/tag/v19.7.0 (Third Party Advisory, Release Notes)
- matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sd… (Vendor Advisory)
- github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-r48r-j8fx-mq2c (Third Party Advisory)
- security.gentoo.org/glsa/202210-35 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2022-39251?
- CVE-2022-39251 is a high-severity vulnerability in Matrix JavaScript Sdk, classified under Improper Authentication. CVSS score: 8.6/10. Published 2022-09-28.
- How severe is CVE-2022-39251?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2022-39251 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.