EUVD-2026-45033Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/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
Network-reachable token endpoint requires low-privileged account and specific configuration preconditions; scope bounded to the BunkerWeb instance with no lateral impact to subsequent systems.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
3DescriptionCVE.org
bunkerweb is an Open-source and next-generation Web Application Firewall (WAF). Prior to BunkerWeb 1.6.12 and BunkerWeb PRO 0.57, authenticated Host header handling in the BunkerWeb UI and API improperly validated and neutralized user-controlled input in a configuration-dependent path, allowing a low-privileged authenticated user to escalate privileges and affect confidentiality, integrity, and availability of the BunkerWeb instance. This issue is fixed in BunkerWeb version 1.6.12 and BunkerWeb PRO version 0.57.
AnalysisAI
Privilege escalation in BunkerWeb's UI and API allows a low-privileged authenticated user to inject attacker-controlled Datalog facts into signed Biscuit authorization tokens by manipulating the HTTP Host header, which was interpolated directly into the token builder string without parameterization. Affected are BunkerWeb open-source versions prior to 1.6.12 and BunkerWeb PRO prior to 0.57. No public exploit identified at time of analysis, but the public commit diff fully documents the injection mechanism, making reproduction straightforward for any authenticated low-privileged account holder.
Technical ContextAI
BunkerWeb is an open-source WAF built on nginx that uses the Biscuit authorization framework for token-based access control. Biscuit tokens embed Datalog-style policy facts that are cryptographically signed and evaluated by an authorizer at runtime. Prior to the fix, the create_token_for_role method in biscuit.py built the token using Python f-string interpolation: domain("{request.host}"). Because request.host is entirely attacker-controlled via the HTTP Host header, a crafted value could close the current Datalog fact and append additional facts - analogous to SQL injection - which would then be signed into the token and evaluated as trusted. The commit diff confirms the fix: parameterized fact binding via Fact("domain({domain})", {"domain": ...}) replaces the vulnerable string interpolation. The same patch batch also resolves related privilege issues: cache route authorization bypass allowing reader-role users to purge the job cache, and permissive hostname validation accepting Datalog metacharacters. CWE-20 (Improper Input Validation) is the correct root cause class - specifically, failure to separate data from code in a structured policy language.
RemediationAI
Upgrade BunkerWeb open-source to version 1.6.12 or later, or BunkerWeb PRO to version 0.57 or later; the patched release is published at https://github.com/bunkerity/bunkerweb/releases/tag/v1.6.12 and the upstream fix commit is https://github.com/bunkerity/bunkerweb/commit/685ccbbe7d204132a843a7b7fd802d1bdb3f20a9. The security advisory is at https://github.com/bunkerity/bunkerweb/security/advisories/GHSA-254j-92cv-m443. If immediate upgrade is not feasible, restrict access to the BunkerWeb UI and API to trusted networks or VPN-authenticated users to eliminate the network attack surface - this does not eliminate the flaw but eliminates remote exploitation. Additionally, audit all low-privileged BunkerWeb accounts and revoke those not operationally required, since PR:L means any account holder is a potential attacker. Note that restricting to read-only roles does not fully mitigate because the injection occurs at token creation time, not at the operation level.
Bypass of rDNS-based security controls in BunkerWeb prior to 1.6.13 allows unauthenticated remote attackers who control
Improper authorization in BunkerWeb's web UI middleware allows authenticated reader-role accounts to permanently delete
Same weakness CWE-20 – Improper Input Validation
View allSame technique Privilege Escalation
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External POC / Exploit Code
Leaving vuln.today