# CVE-2026-9084: MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations

> Attackers can hijack MISP accounts by exploiting OIDC email-based linking when IdP email verification is disabled.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 May 2026
- **Updated:** 20 May 2026
- **Also known as:** GHSA-5895-8h7c-2833

## What is CVE-2026-9084?

CVE-2026-9084 is a medium-severity authentication bypass vulnerability in misp, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

MISP’s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim’s email address and authenticate as that user, leading to account takeover.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-9084?


## How do I fix CVE-2026-9084?

No fix has been published for CVE-2026-9084 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9084 being exploited?

There is no known exploitation of CVE-2026-9084 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9084 and fix it if it is affected.

What it is: CVE-2026-9084 is a medium-severity authentication bypass vulnerability in misp, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-9084 in the wild and no public exploit code.

Affected product: misp. 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-2026-9084/ (Markdown: https://insights.sbomify.com/CVE-2026-9084/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9084
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9084
- OSV: https://osv.dev/vulnerability/CVE-2026-9084

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9084/
Summaries are generated and may contain mistakes; the official description above is the record.