CVE-2026-25555

OpenBullet2 through version 0.3.2 contains an authentication bypass vulnerability in the API key authentication middleware that allows unauthenticated attackers to gain admin access by supplying an empty X-Api-Key header value. Attackers can exploit the middleware's comparison of the supplied header against an empty AdminApiKey default string to access the admin console and all API endpoints without valid credentials.

CVSS v4.0

9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

1.82% chance of exploitation in the next 30 days, 77th percentile

Nuclei

critical · CWE-287

Published

2026-06-08

Updated

2026-07-14

Proof-of-concept exploits (1)

• https://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-25555.yaml

References

• CVE Record
• NVD entry

Related

• CVE-2026-25551
• CVE-2026-25557
• CVE-2026-25548
• CVE-2026-25559
• CVE-2026-25547
• CVE-2026-2556