CVE-2025-27909
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 · uneditedIBM Concert Software 1.0.0 through 1.1.0 uses cross-origin resource sharing (CORS) which could allow an attacker to carry out privileged actions as the domain name is not being limited to only trusted domains.
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 · moderate confidenceIBM Concert Software versions 1.0.0 through 1.1.0 has a CORS misconfiguration that does not restrict the Access-Control-Allow-Origin header to trusted domains. This allows any external origin to make cross-origin requests to the application, potentially enabling attackers to perform privileged actions by tricking authenticated users into visiting malicious sites.
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>= 1.0.0, < 2.0.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 IBM Concert versionLocate the IBM Concert installation and check its version. This may be found in the product's about page, version file, or by querying the service/API if accessible. Common locations include installation directories, configuration files, or the product's built-in version endpoint.Affected if The installed version is 1.0.0 through 1.1.0 (any version >= 1.0.0 and < 2.0.0)
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Locate CORS configurationFind the CORS configuration file or settings for IBM Concert. This is typically in a web server configuration, application configuration, or specific CORS middleware settings. Look for files named cors.json, cors.yaml, or similar, or configuration sections named 'cors' or 'Access-Control-Allow-Origin'.Affected if CORS configuration file or setting exists and is accessible for inspection
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Inspect Access-Control-Allow-Origin header valueExamine the value set for Access-Control-Allow-Origin in the CORS configuration. Check if it is set to a wildcard (*), contains multiple unspecified origins, or lacks explicit origin validation. This may be found in config files, environment variables, or runtime configuration.Affected if Access-Control-Allow-Origin is set to '*' (wildcard) or allows any origin rather than explicitly whitelisted trusted domains
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Verify origin validation is implementedReview the CORS implementation to determine if proper origin validation is in place. Check if the application validates incoming Origin headers against a whitelist before setting Access-Control-Allow-Origin, or if it blindly reflects the Origin header value.Affected if The application does not validate origins and simply allows all origins, or the validation can be bypassed
You are affected if IBM Concert version 1.0.0 through 1.1.0 is installed and the Access-Control-Allow-Origin header is configured with a wildcard or allows any origin without proper validation.
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.
dbcve · scoped2.0.0
Configure CORS to explicitly whitelist only trusted domains in the Access-Control-Allow-Origin header and consider implementing origin validation with additional safeguards like custom headers or token-based origin verification.
2.0.0
- Upgrade IBM Concert Software from version 1.0.0-1.1.x to version 2.0.0 or later
- After upgrade, verify that CORS is properly configured to allow only trusted domains in the IBM Concert settings
- Test that legitimate cross-origin requests from trusted domains still function correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-27909 — 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-2025-27909 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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