# CVE-2026-34460: NamelessMC: OAuth callback `state` is not validated, allowing login CSRF / session swapping

> Attackers can force victims to log in as attacker-controlled accounts via OAuth callback manipulation, leading to session swapping and account takeover.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 2 Jun 2026
- **Updated:** 2 Jun 2026
- **Also known as:** GHSA-pmpw-2xvh-5xj6

## What is CVE-2026-34460?

CVE-2026-34460 is a medium-severity vulnerability in NamelessMC Nameless, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

NamelessMC is website software for Minecraft servers. In versions 2.2.4 and prior, the OAuth callback handling does not validate the state parameter server-side before exchanging the authorization code. This allows an attacker to capture a valid OAuth callback URL for their own account and cause a victim's browser to navigate to it, resulting in the victim's session being authenticated as the attacker-linked account (OAuth login CSRF / session swapping). This is patched in version 2.2.5.

Weakness: CWE-352 (Cross-Site Request Forgery), CWE-346 (Origin Validation Error), CWE-302 (Authentication Bypass by Assumed-Immutable Data)

## Which versions are affected by CVE-2026-34460?


## How do I fix CVE-2026-34460?

No fix has been published for CVE-2026-34460 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-34460 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34460 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34460 and fix it if it is affected.

What it is: CVE-2026-34460 is a medium-severity vulnerability in NamelessMC Nameless, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34460 exists.

Affected product: NamelessMC Nameless. 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-2026-34460/ (Markdown: https://insights.sbomify.com/CVE-2026-34460/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34460
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34460
- OSV: https://osv.dev/vulnerability/CVE-2026-34460

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-34460/
Summaries are generated and may contain mistakes; the official description above is the record.