{"items":[{"id":"NVI-00013978","kind":"vulnerability","title":"HAPI FHIR: SHCParser DEFLATE infinite loop causes denial of service","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-gq9c-wmrm-5hvr","CVE-2026-81876"],"plain_summary":"GitHub lists this reviewed advisory for ca.uhn.hapi.fhir:org.hl7.fhir.r5, ca.uhn.hapi.fhir:org.hl7.fhir.validation, ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-2c04d752b576b094d0f9baa988de5bbe"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-09-17T20:32:25.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-2c04d752b576b094d0f9baa988de5bbe"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-2c04d752b576b094d0f9baa988de5bbe","url":"https://github.com/advisories/GHSA-gq9c-wmrm-5hvr","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-gq9c-wmrm-5hvr","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T14:29:49.409Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-2c04d752b576b094d0f9baa988de5bbe"],"technology":"ca.uhn.hapi.fhir:org.hl7.fhir.r5","known_exclusions":[],"conditions_summary":"### Summary\nA malformed Smart Health Card (SHC) JWT with `zip: \"DEF\"` and an empty or truncated DEFLATE payload causes `SHCParser.inflate()` to loop forever. This allows an attacker who can submit SHC content for validation to pin a JVM worker thread indefinitely, causing denial of service.\n\n### Details\nThe vulnerable code is in `org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java`.\n\n`decodeJWT()` inflates the JWT payload when the header contains `\"zip\":\"DEF\"`:\n\n```java\n// SHCParser.java:300-302\nif (\"DEF\".equals(res.header.asString(\"zip\"))) {\n  payloadJson = inflate(payloadJson);\n}\n```\n\n`inflate()` loops only on `!inflater.finished()` and does not check `inflater.needsInput()`, `inflater.needsDictionary()`, or zero-progress output:\n\n```java\n// SHCParser.java:455-468\nwhile (!inflater.finished()) {\n  final int count = inflater.inflate(buffer);\n  outputStream.write(buffer, 0, count);\n}\n```\n\nFor empty or truncated raw DEFLATE input, `Inflater.inflate()` returns `0`, `finished()` remains `false`, and `needsInput()` becomes `true`, producing an infinite tight loop. The same unsafe loop pattern also exists in `decompress()` at `SHCParser.java:410-423`.\n\nThe validator","public_affected_ranges":["<= 6.9.11"]},{"certainty":"source_listed","source_ids":["sr-2c04d752b576b094d0f9baa988de5bbe"],"technology":"ca.uhn.hapi.fhir:org.hl7.fhir.validation","known_exclusions":[],"conditions_summary":"### Summary\nA malformed Smart Health Card (SHC) JWT with `zip: \"DEF\"` and an empty or truncated DEFLATE payload causes `SHCParser.inflate()` to loop forever. This allows an attacker who can submit SHC content for validation to pin a JVM worker thread indefinitely, causing denial of service.\n\n### Details\nThe vulnerable code is in `org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java`.\n\n`decodeJWT()` inflates the JWT payload when the header contains `\"zip\":\"DEF\"`:\n\n```java\n// SHCParser.java:300-302\nif (\"DEF\".equals(res.header.asString(\"zip\"))) {\n  payloadJson = inflate(payloadJson);\n}\n```\n\n`inflate()` loops only on `!inflater.finished()` and does not check `inflater.needsInput()`, `inflater.needsDictionary()`, or zero-progress output:\n\n```java\n// SHCParser.java:455-468\nwhile (!inflater.finished()) {\n  final int count = inflater.inflate(buffer);\n  outputStream.write(buffer, 0, count);\n}\n```\n\nFor empty or truncated raw DEFLATE input, `Inflater.inflate()` returns `0`, `finished()` remains `false`, and `needsInput()` becomes `true`, producing an infinite tight loop. The same unsafe loop pattern also exists in `decompress()` at `SHCParser.java:410-423`.\n\nThe validator","public_affected_ranges":["<= 6.9.11"]},{"certainty":"source_listed","source_ids":["sr-2c04d752b576b094d0f9baa988de5bbe"],"technology":"ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli","known_exclusions":[],"conditions_summary":"### Summary\nA malformed Smart Health Card (SHC) JWT with `zip: \"DEF\"` and an empty or truncated DEFLATE payload causes `SHCParser.inflate()` to loop forever. This allows an attacker who can submit SHC content for validation to pin a JVM worker thread indefinitely, causing denial of service.\n\n### Details\nThe vulnerable code is in `org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java`.\n\n`decodeJWT()` inflates the JWT payload when the header contains `\"zip\":\"DEF\"`:\n\n```java\n// SHCParser.java:300-302\nif (\"DEF\".equals(res.header.asString(\"zip\"))) {\n  payloadJson = inflate(payloadJson);\n}\n```\n\n`inflate()` loops only on `!inflater.finished()` and does not check `inflater.needsInput()`, `inflater.needsDictionary()`, or zero-progress output:\n\n```java\n// SHCParser.java:455-468\nwhile (!inflater.finished()) {\n  final int count = inflater.inflate(buffer);\n  outputStream.write(buffer, 0, count);\n}\n```\n\nFor empty or truncated raw DEFLATE input, `Inflater.inflate()` returns `0`, `finished()` remains `false`, and `needsInput()` becomes `true`, producing an infinite tight loop. The same unsafe loop pattern also exists in `decompress()` at `SHCParser.java:410-423`.\n\nThe validator","public_affected_ranges":["<= 6.9.11"]}],"null_published_at":"2026-11-02T10:00:37.193Z","source_updated_at":"2026-09-17T20:32:25.000Z","source_disclosed_at":"2026-09-17T20:32:21.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-01T14:29:49.409Z"}],"next_cursor":null,"snapshot_revision":"42594"}