# CVE-2023-5967: Denial of Service via crashing the Calls Plugin > An attacker can crash the Mattermost Calls plugin by sending requests without a User Agent header, causing a denial of service. - **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 6 Nov 2023 - **Updated:** 12 Sep 2024 - **Also known as:** GHSA-xvq6-h898-wcj8 ## What is CVE-2023-5967? CVE-2023-5967 is a medium-severity denial of service vulnerability in Mattermost Mattermost, published on 6 Nov 2023. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description Mattermost fails to properly validate requests to the Calls plugin, allowing an attacker sending a request without a User Agent header to cause a panic and crash the Calls plugin Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions) ## Which versions are affected by CVE-2023-5967? 8 open source packages ship an affected version, including github.com/mattermost/mattermost/server/v8 and github.com/mattermost/mattermost-server/v6. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/mattermost/mattermost/server/v8` | Go | From 8.0.0 | 8.0.4 | | `github.com/mattermost/mattermost/server/v8` | Go | From 8.0.0 | 8.0.4 | | `github.com/mattermost/mattermost/server/v8` | Go | From 8.1.0 | 8.1.3 | | `github.com/mattermost/mattermost/server/v8` | Go | From 8.1.0 | 8.1.3 | | `github.com/mattermost/mattermost/server/v8` | Go | From 9.0.0 | 9.0.1 | | `github.com/mattermost/mattermost/server/v8` | Go | From 9.0.0 | 9.0.1 | | `github.com/mattermost/mattermost-server/v6` | Go | All versions | 7.8.12 | | `github.com/mattermost/mattermost-server/v6` | Go | All versions | 7.8.12 | Products: Mattermost Mattermost. ## How do I fix CVE-2023-5967? Upgrade github.com/mattermost/mattermost/server/v8 to a fixed version for your release line: 8.0.4, 8.1.3 or 9.0.1. ## Is CVE-2023-5967 being exploited? There is no known exploitation of CVE-2023-5967 in the wild and no public exploit code. ## Other vulnerabilities in Mattermost Mattermost - [CVE-2019-20851](https://insights.sbomify.com/CVE-2019-20851/): Path traversal in n/a (critical 9.1) - [CVE-2024-39274](https://insights.sbomify.com/CVE-2024-39274/): Malicious remote can add users to arbitrary teams and channels (high 8.7) - [CVE-2024-39777](https://insights.sbomify.com/CVE-2024-39777/): Malicious remote can invite itself to an arbitrary local channel (high 8.7) - [CVE-2024-39830](https://insights.sbomify.com/CVE-2024-39830/): Timing attack during remote cluster token comparison when shared channels are enabled (high 8.1) - [CVE-2023-3615](https://insights.sbomify.com/CVE-2023-3615/): Lack of server certificate validation in websockets connection (high 8.1) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-5967 and fix it if it is affected. What it is: CVE-2023-5967 is a medium-severity denial of service vulnerability in Mattermost Mattermost, published on 6 Nov 2023. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-5967 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/mattermost/mattermost/server/v8 (Go): affected from 8.0.0; fixed in 8.0.4 - github.com/mattermost/mattermost/server/v8 (Go): affected from 8.0.0; fixed in 8.0.4 - github.com/mattermost/mattermost/server/v8 (Go): affected from 8.1.0; fixed in 8.1.3 - github.com/mattermost/mattermost/server/v8 (Go): affected from 8.1.0; fixed in 8.1.3 - github.com/mattermost/mattermost/server/v8 (Go): affected from 9.0.0; fixed in 9.0.1 - github.com/mattermost/mattermost/server/v8 (Go): affected from 9.0.0; fixed in 9.0.1 - github.com/mattermost/mattermost-server/v6 (Go): affected all versions; fixed in 7.8.12 - github.com/mattermost/mattermost-server/v6 (Go): affected all versions; fixed in 7.8.12 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-2023-5967/ (Markdown: https://insights.sbomify.com/CVE-2023-5967/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-5967 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-5967 - OSV: https://osv.dev/vulnerability/CVE-2023-5967 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-5967/ Summaries are generated and may contain mistakes; the official description above is the record.