CVE-2026-40942Network attack vector

Service interruption via inverted OIDC cache expiration

Published Apr 21, 2026 · Updated Apr 21, 2026

Cache-control errors in Data Sharing Framework before 2.1.0 allow remote attackers to interrupt OIDC-backed service requests. BaseOidcClientWithCache and OidcClientWithCache test cache deadlines with isBefore rather than isAfter, bypassing cached metadata and keys while retaining expired access tokens. Bearer-token authentication, back-channel logout, or OIDC-authenticated FHIR client connections must be enabled; affected requests incur provider round trips, fail when the provider is unavailable, or reuse an expired token.

CVSS severity6.3
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cache-control errors in Data Sharing Framework before 2.1.0 allow remote attackers to interrupt OIDC-backed service requests. BaseOidcClientWithCache and OidcClientWithCache test cache deadlines with isBefore rather than isAfter, bypassing cached metadata and keys while retaining expired access tokens. Bearer-token authentication, back-channel logout, or OIDC-authenticated FHIR client connections must be enabled; affected requests incur provider round trips, fail when the provider is unavailable, or reuse an expired token.

The record

CVE
CVE-2026-40942
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
Data Sharing Framework
Product
Data Sharing Framework
Classifications
CWE-670, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Data Sharing Framework · Data Sharing Frameworkversion=< 2.1.0
Data Sharing Framework · DSF BPE Process API v2version=< 2.1.0
Data Sharing Framework · DSF BPE Serverversion=< 2.1.0

Published CVSS scores

6.3GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-670Always-Incorrect Control Flow Implementation
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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