# CVE-2026-109321: Grav Login OAuth Plugin before 1.4.3 Predictable Local Credentials Authentication Bypass

> Attackers can bypass authentication and gain administrative control by predicting deterministic credentials for OAuth-provisioned accounts.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2026
- **Updated:** 18 Oct 2026
- **Also known as:** GHSA-9qx4-jr52-5c2w, GHSA-mj8v-hvf6-73gm

## What is CVE-2026-109321?

CVE-2026-109321 is a critical authentication bypass vulnerability in getgrav grav-plugin-login-oauth, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Grav Login OAuth plugin (grav-plugin-login-oauth) before 1.4.3 provisions OAuth accounts as ordinary Grav users with a deterministic <provider>.<id> username and an unsalted MD5 hash of the provider identifier as the password, without disabling password login. Unauthenticated remote attackers who learn or guess a provider identifier can reproduce these credentials and log in, gaining administrative control of privileged accounts.

Weakness: CWE-1391 (Use of Weak Credentials)

## Which versions are affected by CVE-2026-109321?


## How do I fix CVE-2026-109321?

No fix has been published for CVE-2026-109321 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-109321 being exploited?

There is no known exploitation of CVE-2026-109321 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109321 and fix it if it is affected.

What it is: CVE-2026-109321 is a critical authentication bypass vulnerability in getgrav grav-plugin-login-oauth, published on 12 Oct 2026. 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-2026-109321 in the wild and no public exploit code.

Affected product: getgrav grav-plugin-login-oauth. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-109321/ (Markdown: https://insights.sbomify.com/CVE-2026-109321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109321
- OSV: https://osv.dev/vulnerability/CVE-2026-109321

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109321/
Summaries are generated and may contain mistakes; the official description above is the record.