CVE-2026-33758 — openbao
Fix: openbao/openbao@6e2b2ddCVE-2026-33758 is a Improper Input Validation vulnerability in github.com/openbao/openbao. A fix is available for github.com/openbao/openbao — see the affected versions and patch details below.
OpenBao has Reflected XSS in its OIDC authentication error message
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33758.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/openbao/openbaoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao installations that have an OIDC/JWT authentication method enabled and a role with callback_mode=direct configured are vulnerable to XSS via the error_description parameter on the page for a failed authentication. This allows an attacker access to the token used in the Web UI by a victim. The error_description parameter has been replaced with a static error message in v2.5.2. The vulnerability can be mitigated by removing any roles with callback_mode set to direct.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/openbao/openbao | all versions | 0.0.0-20260325133417-6e2b2dd84f0ego get github.com/openbao/openbao@v0.0.0-20260325133417-6e2b2dd84f0e |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/openbao/openbao, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/openbao/openbao to 0.0.0-20260325133417-6e2b2dd84f0e or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33758 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33758 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33758. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33758 in your dependencies?
O3 Security finds CVE-2026-33758 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.