# CVE-2025-27909: IBM Concert Software cross-origin resource sharing

> An attacker can perform privileged actions due to overly permissive CORS settings in IBM Concert Software.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 18 Aug 2025
- **Updated:** 18 Aug 2025
- **Also known as:** GHSA-22cj-gf6g-gpgc

## What is CVE-2025-27909?

CVE-2025-27909 is a medium-severity vulnerability in Ibm Concert, published on 18 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

IBM 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.

Weakness: CWE-697 (Incorrect Comparison), CWE-942 (Permissive Cross-domain Security Policy with Untrusted Domains)

## Which versions are affected by CVE-2025-27909?

It affects 1 product.


Products: Ibm Concert.

## How do I fix CVE-2025-27909?

No fix has been published for CVE-2025-27909 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-27909 being exploited?

There is no known exploitation of CVE-2025-27909 in the wild and no public exploit code.

## Other vulnerabilities in Ibm Concert

- [CVE-2026-6721](https://insights.sbomify.com/CVE-2026-6721/): Multiple Vulnerabilities in IBM Concert Software (critical 9.8)
- [CVE-2026-6730](https://insights.sbomify.com/CVE-2026-6730/): Multiple Vulnerabilities in IBM Concert Software (critical 9.8)
- [CVE-2026-6928](https://insights.sbomify.com/CVE-2026-6928/): Multiple Vulnerabilities in IBM Concert Software (critical 9.8)
- [CVE-2026-3627](https://insights.sbomify.com/CVE-2026-3627/): Multiple Vulnerabilities in IBM Concert Software (critical 9.1)
- [CVE-2025-33015](https://insights.sbomify.com/CVE-2025-33015/): Multiple Vulnerabilities in IBM Concert Software (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-27909 and fix it if it is affected.

What it is: CVE-2025-27909 is a medium-severity vulnerability in Ibm Concert, published on 18 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-27909 in the wild and no public exploit code.

Affected product: Ibm Concert. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-27909/ (Markdown: https://insights.sbomify.com/CVE-2025-27909/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-27909
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-27909
- OSV: https://osv.dev/vulnerability/CVE-2025-27909

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-27909/
Summaries are generated and may contain mistakes; the official description above is the record.