# CVE-2026-124447: OpenEMR before 8.3.0 IDOR via OnsitePortalActivityController Update Endpoint

Status: published. Published: 2026-11-08. Updated: 2026-11-10.

OpenEMR before 8.3.0 contains an insecure direct object reference vulnerability in OnsitePortalActivityController::Update() that checks the request's patientId instead of the stored record's owner. Authenticated portal patients can send PUT requests to the onsiteportalactivity API with another patient's activity id and their own patientId to disclose tableArgs and checksum data, overwrite narratives and status, and take ownership of the record.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- openemr / openemr: ≥ 0; < 8.3.0 (affected, semver); 8.3.0 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.6 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 8.1 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N; source: CNA: VulnCheck

- CVSS 4.0: 8.6 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 8.1 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-10; percentile 22.24%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-639

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/openemr/openemr/security/advisories/GHSA-x8rm-m66w-qhh5 (CNA: VulnCheck; vendor-advisory)

- https://github.com/openemr/openemr/security/advisories/GHSA-5hx3-92fw-6jm6 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/openemr-before-8.3.0-idor-via-onsiteportalactivitycontroller-update-endpoint (CNA: VulnCheck; third-party-advisory)

- https://github.com/openemr/openemr/security/advisories/GHSA-5hx3-92fw-6jm6 (disclosure@vulncheck.com)

- https://github.com/openemr/openemr/security/advisories/GHSA-x8rm-m66w-qhh5 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/openemr-before-8.3.0-idor-via-onsiteportalactivitycontroller-update-endpoint (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124447; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124447; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-124447; retrieved 2026-11-10; source updated Not reported

Revision: c172f9877dd9c4114c9d912890db1622f094eefdd994491b3fb6c3638b5ffcfd

Canonical: https://y2.dev/cve/CVE-2026-124447

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.