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.
- 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
- None listed
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.
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.
Sources
Also known as GHSA-pmpw-2xvh-5xj6.