# Mattermost Server server restarts may provide attackers with API access

Advisory record · `GHSA-hxxj-8phw-74vw`

- **Identifiers:** `GHSA-hxxj-8phw-74vw` · `CVE-2017-18915` · `GO-2026-4462`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-20](https://cwe.mitre.org/data/definitions/20.html) · [CWE-807](https://cwe.mitre.org/data/definitions/807.html)
- **Tags:** [CWE-20](https://agentprime.io/advisories/tag/cwe-20.md) · [CWE-807](https://agentprime.io/advisories/tag/cwe-807.md)
- **Published:** 24 May 2022
- **Updated:** 19 Feb 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 24 May 2022, 17:21 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `github.com/mattermost/mattermost-server` (Go): affected `<3.6.7-0.20170420152529-0968e4079e0a || >=3.7.0, <3.7.5 || >=3.8.0, <3.8.2`; fixed in `3.6.7-0.20170420152529-0968e4079e0a`, `3.7.5`, `3.8.2`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.012, the 67th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 24 May 2022. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-hxxj-8phw-74vw](https://github.com/advisories/GHSA-hxxj-8phw-74vw)
- [OSV: GHSA-hxxj-8phw-74vw](https://osv.dev/vulnerability/GHSA-hxxj-8phw-74vw)
- <https://nvd.nist.gov/vuln/detail/CVE-2017-18915>
- <https://github.com/mattermost/mattermost/commit/0968e4079e0aa670254f3fe3a7248d126e3cf877>
- <https://github.com/mattermost/mattermost/commit/c7bdce8a6641ed8d361a43b6004a351535c78423>
- <https://github.com/mattermost/mattermost/commit/fb325cc339eb8d8efb60dbadc48fd38897201c6f>
- <https://github.com/mattermost/mattermost>
- <https://mattermost.com/security-updates>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-hxxj-8phw-74vw>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-hxxj-8phw-74vw/>. Everything for agents: <https://agentprime.io/llms.txt>.