# CVE-2026-40939: DSF: Missing Session Timeout for OIDC Sessions

> Attackers can maintain indefinite access via expired OIDC sessions due to missing inactivity timeouts in the Data Sharing Framework.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Apr 2026
- **Updated:** 22 Apr 2026
- **Also known as:** GHSA-gj7p-595x-qwf5

## What is CVE-2026-40939?

CVE-2026-40939 is a medium-severity missing authorization vulnerability in datasharingframework dsf, published on 21 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Data Sharing Framework (DSF) implements a distributed process engine based on the BPMN 2.0 and FHIR R4 standards. Prior to 2.1.0, OIDC-authenticated sessions had no configured maximum inactivity timeout. Sessions persisted indefinitely after login, even after the OIDC access token expired. This vulnerability is fixed in 2.1.0.

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2026-40939?

6 open source packages ship an affected version, including dev.dsf:dsf-bpe-server, dev.dsf:dsf-common-jetty and dev.dsf:dsf-fhir-server.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dev.dsf:dsf-bpe-server` | Maven | All versions | None |
| `dev.dsf:dsf-bpe-server` | Maven | All versions | None |
| `dev.dsf:dsf-common-jetty` | Maven | All versions | None |
| `dev.dsf:dsf-common-jetty` | Maven | All versions | None |
| `dev.dsf:dsf-fhir-server` | Maven | All versions | None |
| `dev.dsf:dsf-fhir-server` | Maven | All versions | None |

## How do I fix CVE-2026-40939?

No fix has been published for CVE-2026-40939 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40939 being exploited?

There is no known exploitation of CVE-2026-40939 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40939 and fix it if it is affected.

What it is: CVE-2026-40939 is a medium-severity missing authorization vulnerability in datasharingframework dsf, published on 21 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40939 in the wild and no public exploit code.

Affected packages and fixed versions:
- dev.dsf:dsf-bpe-server (Maven): affected all versions; no fix listed
- dev.dsf:dsf-bpe-server (Maven): affected all versions; no fix listed
- dev.dsf:dsf-common-jetty (Maven): affected all versions; no fix listed
- dev.dsf:dsf-common-jetty (Maven): affected all versions; no fix listed
- dev.dsf:dsf-fhir-server (Maven): affected all versions; no fix listed
- dev.dsf:dsf-fhir-server (Maven): affected all versions; no fix listed

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-2026-40939/ (Markdown: https://insights.sbomify.com/CVE-2026-40939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40939
- OSV: https://osv.dev/vulnerability/CVE-2026-40939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40939/
Summaries are generated and may contain mistakes; the official description above is the record.