CVE-2026-25555
CriticalPublic exploitOpenBullet2 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.
Published Jun 8, 2026 · Updated Aug 12, 2026
Key Facts
Patch immediately- CVE-2026-25555 is a critical-severity vulnerability (CVSS 9.3 v4) affecting openbullet2.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 2.7% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
CVSS v4
9.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS (30-day exploit likelihood)
2.7%
Higher than 85.8% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-25555 brief as a PDF
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Description
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.
Affected Products
1 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| openbullet2 | See advisory | n/a |
Timeline
Publicly disclosed
Jun 8, 2026
Last updated
Aug 12, 2026
Weakness Type
- CWE-305 Authentication Bypass by Primary Weakness
References
- advisoryhttps://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25555.json
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-25555
- otherhttps://github.com/openbullet/openbullet2
- otherhttps://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2
- otherhttps://www.vulncheck.com/advisories/openbullet2-authentication-bypass-via-x-api-key-header
FAQ
Common Questions.
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.
Affected: openbullet2. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
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