How severe is CVE-2026-40942?

No CVSS score has been assigned to CVE-2026-40942 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-40942?

CVE-2026-40942 affects the following packages: dev.dsf:dsf-bpe-process-api-v2 (Maven), dev.dsf:dsf-bpe-server (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-40942?

No patched version of dev.dsf:dsf-bpe-process-api-v2 has shipped for CVE-2026-40942 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2026-40942 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dev.dsf:dsf-bpe-process-api-v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-40942 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2026-40942?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40942 can be triaged on real exposure rather than presence alone.

Is CVE-2026-40942 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-40942 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-40942?

CVE-2026-40942 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-40942?

CVE-2026-40942 is classified as CWE-670 (CWE-670). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-40942 published, and has it been updated?

CVE-2026-40942 was published on April 21, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-40942 — dsf-bpe-process-api-v2

Fix: datasharingframework/dsf@31c2e97

CVE-2026-40942 is a CWE-670 vulnerability in dev.dsf:dsf-bpe-process-api-v2. No vendor fix is recorded yet; mitigation options are listed below.

DSF: Inverted Time Comparison in OIDC JWKS and Token Cache

Also known asGHSA-xmj9-7625-f634

Published

Apr 21, 2026

Updated

Aug 12, 2026

Affected

2 pkgs

Patched

See advisory

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-2026-40942.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

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

2 pkgs affected

☕dev.dsf:dsf-bpe-process-api-v2☕dev.dsf:dsf-bpe-server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Affected Components

DSF FHIR Server with enabled bearer-token authentication or back-channel logout.
DSF BPE Server with enabled bearer-token authentication or back-channel logout.
DSF BPE Server API v2 process plugins using FHIR client connections with configured OIDC authentication.

Summary

The OIDC JWKS and Metadata Document caches used an inverted time comparison (isBefore instead of isAfter), causing the cache to never return cached values. Every incoming request triggered a fresh HTTP fetch of the OIDC Metadata Document and JWKS keys from the OIDC provider.
The OIDC token cache for the FHIR client connections used an inverted time comparison (isBefore instead of isAfter), causing the cache to never invalidate. Every incoming request returned the same OIDC token even if expired.

Impact

Performance: Every OIDC-authenticated request added network round-trips to the OIDC provider, increasing latency
Reliability: Cached OIDC tokens become unusable after expiration and can only be invalidated by restart of the BPE. If the OIDC provider is temporarily unreachable, all requests fail immediately instead of using cached keys
Load: Unnecessary load on the OIDC provider, potentially causing rate limiting

Fix (commits 31c2e974d, d3ca59b4d)

Fixed cache timeout comparison from isBefore to isAfter in BaseOidcClientWithCache (configuration and JWKS caches) and OidcClientWithCache (configuration, JWKS, and access token caches)
Added configurable cache timeouts via dev.dsf.server.auth.oidc.provider.client.cache.timeout.configuration.resource and dev.dsf.server.auth.oidc.provider.client.cache.timeout.jwks.resource (default: PT1H)

Affected Packages

2 total

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`dev.dsf:dsf-bpe-process-api-v2`	all versions	No fix
☕Maven	`dev.dsf:dsf-bpe-server`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dev.dsf:dsf-bpe-process-api-v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of dev.dsf:dsf-bpe-process-api-v2 has shipped for CVE-2026-40942 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2026-40942 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-40942. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Affected Components - DSF FHIR Server with enabled [bearer-token authentication](https://dsf.dev/operations/v2.1.0/fhir/oidc.html) or [back-channel logout](https://dsf.dev/operations/v2.1.0/fhir/oidc.html). - DSF BPE Server with enabled [bearer-token authentication](https://dsf.dev/operations/v2.1.0/bpe/oidc.html) or [back-channel logout](https://dsf.dev/operations/v2.1.0/bpe/oidc.html). - DSF BPE Server API v2 process plugins using [FHIR client connections](https://dsf.dev/operations/v2.1.0/bpe/fhir-client-connections.html) with configured OIDC authentication. ### Summary - The OIDC JWKS

O3 Security · Impact-Aware SCA

Is CVE-2026-40942 in your dependencies?

O3 Security finds CVE-2026-40942 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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