CVE-2026-40939

Unauthorized access via unexpired OIDC browser sessions

Published Apr 21, 2026 · Updated Apr 21, 2026

Insufficient session expiration in Data Sharing Framework before 2.1.0 allows physically proximate attackers to reuse OIDC browser sessions. AbstractJettyConfig configured neither Jetty's maximum inactive interval nor logout on ID-token expiry, so authenticated browser sessions remained valid indefinitely. Exploitation requires OIDC authentication, a user who leaves a shared browser without logging out, and physical access to that browser; mTLS machine communication is unaffected.

CVSS severity6.8
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient session expiration in Data Sharing Framework before 2.1.0 allows physically proximate attackers to reuse OIDC browser sessions. AbstractJettyConfig configured neither Jetty's maximum inactive interval nor logout on ID-token expiry, so authenticated browser sessions remained valid indefinitely. Exploitation requires OIDC authentication, a user who leaves a shared browser without logging out, and physical access to that browser; mTLS machine communication is unaffected.

The record

CVE
CVE-2026-40939
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
Data Sharing Framework
Product
DSF FHIR Server
Classifications
CWE-613, T1550.004
Attack vector
physical
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 vectorphysical
Required privilegesunauthenticated

What is affected?

Data Sharing Framework · DSF FHIR Serverversion=< 2.1.0
Data Sharing Framework · DSF Common Jettyversion=< 2.1.0
Data Sharing Framework · Data Sharing Frameworkversion=< 2.1.0
Data Sharing Framework · DSF BPE Serverversion=< 2.1.0

Published CVSS scores

6.8GitHubCVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
T1550.004Use Alternate Authentication Material: Web Session Cookie

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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