# CVE-2022-39249: Matrix Javascript SDK vulnerable to impersonation via forwarded Megolm sessions > Attackers can impersonate users by exploiting permissive key forwarding, requiring a malicious homeserver and attacker coordination to bypass identity verification. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Sep 2022 - **Updated:** 23 Apr 2025 - **Also known as:** CLEANSTART-2024-QT51844, DEBIAN-CVE-2022-39249, GHSA-6263-x97c-c4gg, UBUNTU-CVE-2022-39249 ## What is CVE-2022-39249? CVE-2022-39249 is a high-severity authentication bypass vulnerability in matrix-org matrix-js-sdk, published on 28 Sep 2022. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description 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 appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-js-sdk implementing a too permissive key forwarding strategy on the receiving end. Starting with version 19.7.0, the default policy for accepting key forwards has been made more strict in the matrix-js-sdk. matrix-js-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately, for example, by showing a warning for such messages. This attack requires coordination between a malicious homeserver and an attacker, and those who trust your homeservers do not need a workaround. Weakness: CWE-322 (Key Exchange without Entity Authentication), CWE-287 (Improper Authentication) ## Which versions are affected by CVE-2022-39249? 2 open source packages ship an affected version, including matrix-js-sdk. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `matrix-js-sdk` | npm | All versions | 19.7.0 | | `matrix-js-sdk` | npm | All versions | 19.7.0 | Products: Matrix Javascript Sdk. ## How do I fix CVE-2022-39249? Upgrade matrix-js-sdk to 19.7.0 or later. ## Is CVE-2022-39249 being exploited? There is no known exploitation of CVE-2022-39249 in the wild and no public exploit code. ## Other vulnerabilities in matrix-org matrix-js-sdk - [CVE-2022-39250](https://insights.sbomify.com/CVE-2022-39250/): Matrix JavaScript SDK vulnerable to key/device identifier confusion in SAS verification (high 8.6) - [CVE-2022-39251](https://insights.sbomify.com/CVE-2022-39251/): Matrix Javascript SDK vulnerable to Olm/Megolm protocol confusion (high 8.6) - [CVE-2022-36059](https://insights.sbomify.com/CVE-2022-36059/): Prototype pollution in matrix-js-sdk (high 8.2) - [CVE-2023-28427](https://insights.sbomify.com/CVE-2023-28427/): Prototype pollution in matrix-js-sdk (high 8.2) - [CVE-2021-40823](https://insights.sbomify.com/CVE-2021-40823/): matrix-js-sdk can be tricked into disclosing E2EE room keys to a participating homeserver (medium 5.9) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2022-39249 and fix it if it is affected. What it is: CVE-2022-39249 is a high-severity authentication bypass vulnerability in matrix-org matrix-js-sdk, published on 28 Sep 2022. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2022-39249 in the wild and no public exploit code. Affected packages and fixed versions: - matrix-js-sdk (npm): affected all versions; fixed in 19.7.0 - matrix-js-sdk (npm): affected all versions; fixed in 19.7.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2022-39249/ (Markdown: https://insights.sbomify.com/CVE-2022-39249/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2022-39249 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-39249 - OSV: https://osv.dev/vulnerability/CVE-2022-39249 --- From sbomify Insights: https://insights.sbomify.com/CVE-2022-39249/ Summaries are generated and may contain mistakes; the official description above is the record.