CVE-2019-9580
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn st2web in StackStorm Web UI before 2.9.3 and 2.10.x before 2.10.3, it is possible to bypass the CORS protection mechanism via a "null" origin value, potentially leading to XSS.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe st2web component in StackStorm Web UI fails to properly validate the Origin header in CORS requests, allowing attackers to bypass CORS restrictions by using a 'null' origin value. This originates from the application not filtering out the 'null' origin which can be set in various contexts (file://, data:, sandboxed iframes), potentially enabling cross-origin attacks including XSS.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2.9.3>= 2.10.0, < 2.10.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed StackStorm Web UI versionCheck the st2web package version by inspecting the installed st2web package. In typical installations, this can be found via the package manager (dpkg/rpm) or by examining the web UI bundle in /usr/share/st2web or similar installation directories. Look for a version file or package metadata.Affected if The installed version is below 2.9.3, or is between 2.10.0 and 2.10.2 inclusive.
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Confirm CORS is enabled in the environmentExamine the StackStorm configuration files for CORS settings. Look in /etc/st2/st2.conf or equivalent configuration paths for sections related to CORS, 'allow_origin', or 'cors' settings. Check if cors.enabled or similar flags are set to true.Affected if CORS is enabled and the installed version falls within the affected range.
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Inspect the Origin header validation logicReview the st2web source code or configuration that handles Origin header validation in CORS requests. Look for code that processes the Origin header value, specifically whether there is logic to reject or filter 'null' origins.Affected if The validation does not explicitly reject the 'null' origin value, leaving the bypass possible.
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Check for explicit allowlist configurationExamine whether the CORS implementation uses an explicit allowlist of permitted origins, rather than a permissive or incomplete validation approach. Look for configuration options that specify allowed origins explicitly.Affected if There is no explicit allowlist that rejects untrusted origins including 'null', or the allowlist is not being enforced properly.
You are affected if StackStorm Web UI version is below 2.9.3 or between 2.10.0-2.10.2, CORS is enabled, and the 'null' origin is not explicitly rejected in the origin validation logic.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data2.9.32.10.3
Upgrade to StackStorm Web UI version 2.9.3 or 2.10.3 and later, and implement explicit allowlist-based origin validation that rejects 'null' and untrusted origins.
- Consultation4.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9580 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-9580 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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