OpenBao's System Backend allows Unauthorized Management of the containing Namespace

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao users granted capabilities on /sys/namespaces/root within a non-root namespace could exploit special handling of the literal root path in namespace canonicalization. The /sys/namespaces/* endpoint family can resolve its containing namespace through a path prefix or X-Vault-Namespace header. ACL checks occurred before root canonicalized to an empty path, causing /sys/namespaces/root to resolve to the system backend's containing namespace and allowing permitted lookups, deletion, locking, or custom metadata changes against that direct containing namespace. The root namespace and arbitrary unrelated namespaces are not affected, and available operations depend on the capabilities granted on the path and subpaths such as /api-lock. This issue is fixed in version 2.5.5.

Source published

15 Sep 2026 15:40:32 UTC

Source modified

15 Sep 2026 18:02:19 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao users granted capabilities on /sys/namespaces/root within a non-root namespace could exploit special handling of the literal root path in namespace canonicalization. The /sys/namespaces/* endpoint family can resolve its containing namespace through a path prefix or X-Vault-Namespace header. ACL checks occurred before root canonicalized to an empty path, causing /sys/namespaces/root to resolve to the system backend's containing namespace and allowing permitted lookups, deletion, locking, or custom metadata changes against that direct containing namespace. The root namespace and arbitrary unrelated namespaces are not affected, and available operations depend on the capabilities granted on the path and subpaths such as /api-lock. This issue is fixed in version 2.5.5.

Source published

Sep 15, 2026, 3:40:32 PM (timezone not stated)

Source modified

Sep 15, 2026, 6:02:19 PM (timezone not stated)

Observed here

11 Nov 2026 14:04:35 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao users granted capabilities on /sys/namespaces/root within a non-root namespace could exploit special handling of the literal root path in namespace canonicalization. The /sys/namespaces/* endpoint family can resolve its containing namespace through a path prefix or X-Vault-Namespace header. ACL checks occurred before root canonicalized to an empty path, causing /sys/namespaces/root to resolve to the system backend's containing namespace and allowing permitted lookups, deletion, locking, or custom metadata changes against that direct containing namespace. The root namespace and arbitrary unrelated namespaces are not affected, and available operations depend on the capabilities granted on the path and subpaths such as /api-lock. This issue is fixed in version 2.5.5.

Source published

15 Sep 2026 16:17:16 UTC

Source modified

25 Sep 2026 14:23:59 UTC

Observed here

25 Oct 2026 14:19:05 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/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

### Summary A user that is granted namespace management (`/sys/namespaces`) capabilities within a non-root namespace ("the victim namespace") can abuse special handling of the literal path `"root"` in namespace path canonicalization to manage the victim namespace itself. ### Details Several endpoints under `/sys/namespaces/*` accept a namespace path segment that is canonicalized and then appended to the path of the sys mount's containing namespace (set via path prefix or `X-Vault-Namespace` header) to determine the absolute path of the namespace to operate on. Given the special namespace path `"root"` canonicalizes to en empty path (`""`), when passed as `/sys/namespaces/root`, the resulting absolute namespace path remains equal to the sys mount's containing namespace. Given ACLs are evaluated before namespace path canonicalization, this allows users with capabilities on `/sys/namespaces/root` within any given namespace to operate on the namespace itself instead. ### Impact Users that were granted the required capabilities can abuse this vulnerability to: - Look up - Delete - Lock - Patch custom metadata against the namespace containing the system backend they can manage `sys/namespaces/root` in. The exact range of operations that can be performed depends on the specific capabilities granted on said path and any sub-paths such as `/api-lock`. Notably, the root namespace is immutable and cannot be modified, deleted or locked, and is thus unaffected. Also note that users can only abuse this vulnerability to operate on the direct parent or "containing" namespace relative to their capabilities, not arbitrary namespaces. ### Patch This will be fixed in OpenBao v2.5.5. ### PoC Start a development server: ```sh bao server -dev ``` Create a namespace: ```sh bao namespace create victim ``` This will be the namespace we gain unauthorized management of. Create a policy that allows management of namespaces, _inside_ of the victim namespace. ```sh bao policy write -namespace=victim namespace-management - <<EOF path "sys/namespaces/*" { capabilities = ["read", "update", "patch", "delete"] } EOF ``` Then create a token with above policy attached: ```sh export BAO_TOKEN=$(bao token create -namespace=victim -policy=namespace-management -field=token) ``` Operate on the victim's namespace using the token, for example by outright deleting it: ```sh bao namespace delete -namespace=victim root ```

Source published

19 Jun 2026 21:42:06 UTC

Source modified

25 Sep 2026 14:25:33 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Publisher rating · LOW

OpenBao's System Backend allows Unauthorized Management of the containing Namespace in github.com/openbao/openbao

Source published

25 Jun 2026 22:34:34 UTC

Source modified

25 Sep 2026 14:25:33 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.