CVE-2022-39250 is a high-severity (CVSS 8.6) Improper Authentication vulnerability in matrix-js-sdk. A fix is available for matrix-js-sdk — see the affected versions and patch details below.
Matrix JavaScript SDK vulnerable to key/device identifier confusion in SAS verification
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-39250.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-39250 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
matrix-js-sdknpmDescription
Impact
An attacker cooperating with a malicious homeserver could interfere with the verification flow between two users, injecting its own cross-signing user identity in place of one of the users’ identities, leading to the other device trusting/verifying the user identity under the control of the homeserver instead of the intended one.
The vulnerability is a bug in the matrix-js-sdk, caused by checking and signing user identities and devices in two separate steps, and inadequately fixing the keys to be signed between those steps.
Even though the attack is partly made possible due to the design decision of treating cross-signing user identities as Matrix devices on the server side (with their device ID set to the public part of the user identity key), no other examined implementations were vulnerable.
Patches
The matrix-js-sdk has been modified to double check that the key signed is the one that was verified instead of just referencing the key by ID. An additional check has been made to report an error when one of the device ID matches a cross-signing key.
Workarounds
As this attack requires coordination between a malicious homeserver and an attacker -- if you trust your homeserver no particular workaround is needed.
As a potential way of detecting compromise, it’s possible to review your device list or the device list of other users for devices with IDs in the form of a base64 cross-signing key (5XaczGNlfz0bl8R1IX5qn+tBoue2tWJqLMh+SDUuvCk) instead of classical device ID (SEHACYDHMG).
References
For more information
If you have any questions or comments about this advisory, e-mail us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | matrix-js-sdk | all versions | 19.7.0npm install matrix-js-sdk@19.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-js-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update matrix-js-sdk to 19.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-39250 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-39250 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-39250. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 7 | thunderbird-0:102.4.0-1.el7_9 | RHSA-2022:7184 |
| Red Hat Enterprise Linux 8 | thunderbird-0:102.4.0-1.el8_6 | RHSA-2022:7190 |
| Red Hat Enterprise Linux 8.1 Update Services for SAP Solutions | thunderbird-0:102.4.0-1.el8_1 | RHSA-2022:7183 |
| Red Hat Enterprise Linux 8.2 Extended Update Support | thunderbird-0:102.4.0-1.el8_2 | RHSA-2022:7182 |
| Red Hat Enterprise Linux 8.4 Extended Update Support | thunderbird-0:102.4.0-1.el8_4 | RHSA-2022:7181 |
| Red Hat Enterprise Linux 9 | thunderbird-0:102.4.0-1.el9_0 | RHSA-2022:7178 |
Frequently Asked Questions
Is CVE-2022-39250 in your dependencies?
O3 Security finds CVE-2022-39250 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.