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Fencer Intel
medium 5.4

CVE-2026-34460 json

NamelessMC: OAuth callback `state` is not validated, allowing login CSRF / session swapping

published 5mo ago modified 3mo ago also EUVD-2026-33960

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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.

Patch / fix

  • namelessmc nameless 2.2.5

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/NamelessMC/Nameless/security/advisories/GHSA-pmpw-2xvh-5xj6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected products

  • NamelessMC Nameless

Classification

Weakness
  • CWE-302 Authentication Bypass by Assumed-Immutable Data
  • CWE-346 Origin Validation Error
  • CWE-352 Cross-Site Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.