# CVE-2025-13821: User profile update exposes password hash and MFA secrets > Authenticated users can exfiltrate password hashes and MFA secrets via unsanitized WebSocket messages in Mattermost. - **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 16 Feb 2026 - **Updated:** 17 Feb 2026 - **Also known as:** GHSA-pp9j-pf5c-659x, GO-2026-4524 ## What is CVE-2025-13821? CVE-2025-13821 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 16 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link. ### Official description Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. Mattermost Advisory ID: MMSA-2025-00560 Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) ## Which versions are affected by CVE-2025-13821? 17 open source packages ship an affected version, including github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server/v5 and github.com/mattermost/mattermost-server/v6. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/mattermost/mattermost-server` | Go | All versions | None | | `github.com/mattermost/mattermost-server` | Go | All versions | 5.3.2-0.20251210191531-cd17b61de41b | | `github.com/mattermost/mattermost-server` | Go | All versions | 5.3.2-0.20251210191531-cd17b61de41b | | `github.com/mattermost/mattermost-server` | Go | From 10.11.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 10.11.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 10.11.0+incompatible | None | | `github.com/mattermost/mattermost-server` | Go | From 11.1.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 11.1.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 11.1.0+incompatible | None | | `github.com/mattermost/mattermost-server` | Go | From 11.2.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 11.2.0 | None | | `github.com/mattermost/mattermost-server` | Go | From 11.2.0+incompatible | None | | `github.com/mattermost/mattermost-server/v5` | Go | All versions | None | | `github.com/mattermost/mattermost-server/v6` | Go | All versions | None | | `github.com/mattermost/mattermost/server/v8` | Go | All versions | 8.0.0-20251210191531-cd17b61de41b | | `github.com/mattermost/mattermost/server/v8` | Go | All versions | 8.0.0-20251210191531-cd17b61de41b | | `github.com/mattermost/mattermost/server/v8` | Go | All versions | 8.0.0-20251210191531-cd17b61de41b | Products: Mattermost Mattermost Server. ## How do I fix CVE-2025-13821? Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20251210191531-cd17b61de41b or later. ## Is CVE-2025-13821 being exploited? There is no known exploitation of CVE-2025-13821 in the wild and no public exploit code. ## Other vulnerabilities in Mattermost Mattermost Server - [CVE-2025-12419](https://insights.sbomify.com/CVE-2025-12419/): Account takeover on OAuth/OpenID-enabled servers (critical 9.9) - [CVE-2025-12421](https://insights.sbomify.com/CVE-2025-12421/): Account Takeover via Code Exchange Endpoint (critical 9.9) - [CVE-2025-4981](https://insights.sbomify.com/CVE-2025-4981/): Path Traversal Leading to RCE by Any Authenticated Mattermost User (critical 9.9) - [CVE-2025-20051](https://insights.sbomify.com/CVE-2025-20051/): Arbitrary file read via block duplication in Mattermost Boards (critical 9.9) - [CVE-2025-25279](https://insights.sbomify.com/CVE-2025-25279/): Arbitrary file read in Mattermost Boards via import & export board archive (critical 9.9) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-13821 and fix it if it is affected. What it is: CVE-2025-13821 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 16 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2025-13821 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/mattermost/mattermost-server (Go): affected all versions; no fix listed - github.com/mattermost/mattermost-server (Go): affected all versions; fixed in 5.3.2-0.20251210191531-cd17b61de41b - github.com/mattermost/mattermost-server (Go): affected all versions; fixed in 5.3.2-0.20251210191531-cd17b61de41b - github.com/mattermost/mattermost-server (Go): affected from 10.11.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 10.11.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 10.11.0+incompatible; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.1.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.1.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.1.0+incompatible; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.2.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.2.0; no fix listed - github.com/mattermost/mattermost-server (Go): affected from 11.2.0+incompatible; no fix listed 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-2025-13821/ (Markdown: https://insights.sbomify.com/CVE-2025-13821/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-13821 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-13821 - OSV: https://osv.dev/vulnerability/CVE-2025-13821 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-13821/ Summaries are generated and may contain mistakes; the official description above is the record.