# Low-privileged Grav API users can create super-admin accounts via blueprint-upload

Advisory record · `GHSA-6xx2-m8wv-756h`

- **Identifiers:** `GHSA-6xx2-m8wv-756h` · `CVE-2026-42844` · `PKSA-jtpz-17pm-t9v9`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-269](https://cwe.mitre.org/data/definitions/269.html) · [CWE-434](https://cwe.mitre.org/data/definitions/434.html)
- **Tags:** [Privilege escalation](https://agentprime.io/advisories/tag/privilege-escalation.md) · [Unrestricted file upload](https://agentprime.io/advisories/tag/file-upload.md)
- **Published:** 6 May 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 6 May 2026, 21:19 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `getgrav/grav` (Packagist): affected `<2.0.0-beta.4`; fixed in `2.0.0-beta.4`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Grav versions before 2.0.0-beta.4 (the getgrav/grav Packagist package) have a flaw in the API plugin's /api/v1/blueprint-upload endpoint, which lets caller-supplied destination and scope values choose the write target. An authenticated API user with the api.media.write permission could use this to place a YAML account file in the user accounts directory and then log in as that account with super-admin API access. The fix is to upgrade to 2.0.0-beta.4 or later.

Written 31 Oct 2026.

## 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

- 8.7 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0034, the 27th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:02 UTC: First seen by agentprime
- 31 Oct 2026, 14:02 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-6xx2-m8wv-756h)

## Sources

- [GitHub Advisory Database: GHSA-6xx2-m8wv-756h](https://github.com/advisories/GHSA-6xx2-m8wv-756h)
- [OSV: GHSA-6xx2-m8wv-756h](https://osv.dev/vulnerability/GHSA-6xx2-m8wv-756h)
- <https://github.com/getgrav/grav/security/advisories/GHSA-6xx2-m8wv-756h>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-42844>
- <https://github.com/getgrav/grav-plugin-api/commit/97fc02844a35f743dfe93d34efd92d47eedd5bc5>
- <https://github.com/getgrav/grav>

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-6xx2-m8wv-756h>, 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-6xx2-m8wv-756h/>. Everything for agents: <https://agentprime.io/llms.txt>.