CVE-2026-55775: 
Wolfi vulnerability analysis and mitigation

CVE-2026-55775 is an improper authorization vulnerability in OpenBao's System Backend that allows authenticated users with namespace management capabilities to bypass namespace isolation boundaries. Specifically, a user granted /sys/namespaces capabilities within a non-root namespace can abuse special handling of the literal path "root" in namespace path canonicalization to operate on the containing (parent) namespace itself. Affected versions are all OpenBao releases from >= 0.1.0 through <= 2.5.4; the fix is included in OpenBao v2.5.5. The CVSSv4 base score is 2.3 (Low), though the Feedly category estimate rates it as HIGH due to its potential impact in multi-tenant deployments (GitHub Advisory, OpenBao Advisory).

The root cause is improper authorization (CWE-285) arising from a logic flaw in namespace path canonicalization within OpenBao's helper/namespace/namespace.go. The Canonicalize() function previously treated the literal string "root" identically to ".", resolving both to an empty path (""). Because ACL evaluation occurs before path canonicalization, a user with capabilities on /sys/namespaces/root passes the ACL check (which sees the literal path root), but the subsequent canonicalization resolves the path to empty — causing the operation to target the sys mount's containing namespace rather than a child namespace named root. This affects multiple endpoints under /sys/namespaces/* including read, set, patch, delete, seal, unseal, and API-lock operations. The fix introduces a new ParseName() function that validates the namespace name after canonicalization and explicitly rejects empty or reserved names, and removes the special-case treatment of "root" in Canonicalize() (OpenBao Advisory, Fix Commit).

An authenticated attacker with namespace management capabilities (/sys/namespaces) in any non-root namespace can look up, delete, lock, or patch custom metadata of the direct parent (containing) namespace — effectively breaking namespace isolation in multi-tenant OpenBao deployments. Deletion or locking of a parent namespace could cause significant availability disruption for all tenants within that namespace. The root namespace itself is immutable and unaffected, and exploitation is limited to the direct parent namespace rather than arbitrary namespaces (OpenBao Advisory).

No public proof-of-concept exploit code has been published, and there is no evidence of in-the-wild exploitation at this time. Exploitation requires an authenticated user with explicitly granted namespace management capabilities (/sys/namespaces) within a non-root namespace, limiting the attack surface to privileged but non-administrative users in multi-tenant environments. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no EPSS score is currently available (GitHub Advisory, OpenBao Advisory).

1. Prerequisite: Obtain an authenticated OpenBao token with capabilities (e.g., read, delete, update) on the path /sys/namespaces/root within a non-root namespace (e.g., victim/).
2. Set namespace context: Configure the X-Vault-Namespace header or path prefix to target the non-root namespace where the token's policy applies (e.g., victim/).
3. Send crafted request: Issue an API request to /v1/sys/namespaces/root using the desired operation (GET to look up, DELETE to delete, POST to patch metadata, etc.) with the namespace header set to victim/.
4. Bypass ACL check: The ACL engine evaluates the literal path /sys/namespaces/root and grants access based on the token's policy.
5. Trigger canonicalization flaw: The Canonicalize("root") function resolves "root" to an empty string, causing the absolute namespace path to resolve to victim/ (the containing namespace) rather than a child namespace named root.
6. Achieve unauthorized operation: The operation is executed against the victim/ namespace itself — for example, deleting or locking it — rather than a child namespace, bypassing the intended namespace isolation boundary (OpenBao Advisory, Fix Commit).

• Logs: OpenBao audit logs showing requests to /v1/sys/namespaces/root (or equivalent) from tokens operating within a non-root namespace context, particularly DELETE, POST (patch), or lock/unlock operations targeting that path.
• Logs: Unexpected namespace deletion, lock, or metadata modification events in the audit log for a namespace that should not have been managed by the requesting token.
• Network: API calls to /sys/namespaces/root with a non-empty X-Vault-Namespace header value pointing to a non-root namespace.
• Behavioral: Sudden unavailability of a namespace (locked or deleted) without corresponding administrative action from a root-level administrator.

Upgrade OpenBao to v2.5.5 or later, which fixes the namespace path canonicalization flaw via commit d3c1cc64b1ae (OpenBao v2.5.5 Release). As an interim workaround, review and restrict all ACL policies that grant capabilities on /sys/namespaces/root within non-root namespaces, removing such grants from any non-administrative tokens. For sensitive multi-tenant deployments, audit namespace management capability assignments and ensure only fully trusted administrators hold such permissions (OpenBao Advisory).