CVE-2026-33180: HAPI FHIR HTTP authentication leak in redirects

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven) < 6.9.0, fixed in 6.9.0; ca.uhn.hapi.fhir:org.hl7.fhir.convertors (Maven) < 6.9.0, fixed in 6.9.0; ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 (Maven) < 6.9.0, fixed in 6.9.0; ca.uhn.hapi.fhir:org.hl7.fhir.dstu3 (Maven) < 6.9.0, fixed in 6.9.0. Check your lockfile, including transitive dependencies.

What it is

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.0, when setting headers in HTTP requests, the internal HTTP client sends headers first to the host in the initial URL but also, if asked to follow redirects and a 30X HTTP response code is returned, to the host mentioned in URL in the Location: response header value. Sending the same set of headers to subsequent hosts is a problem as this header often contains privacy sensitive information or data that could allow others to impersonate the client's request. This issue has been patched in release 6.9.0. No known workarounds are available.

From the GitHub advisory

Impact When setting headers in HTTP requests, the internal HTTP client sends headers first to the host in the initial URL but also, if asked to follow redirects and a 30X HTTP response code is returned, to the host mentioned in URL in the Location: response header value.

Sending the same set of headers to subsequent hosts is a problem as this header often contains privacy sensitive information or data that could allow others to impersonate the client's request.

Patches This issue has been patched in release 6.8.3

Workarounds None.

Weakness type: CWE-200, CWE-201.

Product: ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven) · Assigned by: GitHub_M · Published: 2026-03-20

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.49% probability of exploitation activity in the next 30 days; percentile 41.

Timeline

• 2026-03-18 — GitHub-reviewed advisory GHSA-p7m9-v2cm-2h7m published (critical)
• 2026-03-20 — CVE record published by GitHub_M
• 2026-07-15 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-p7m9-v2cm-2h7m github.com
2. CVE.org record CVE-2026-33180 cve.org
3. NVD entry CVE-2026-33180 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. access.redhat.com access.redhat.com
3. RHBZ#2449841 bugzilla.redhat.com
4. security.access.redhat.com security.access.redhat.com

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