GHSA-gq9c-wmrm-5hvr

Suggest an improvement
Source
https://github.com/advisories/GHSA-gq9c-wmrm-5hvr
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-gq9c-wmrm-5hvr/GHSA-gq9c-wmrm-5hvr.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-gq9c-wmrm-5hvr
Aliases
Published
2026-09-17T20:32:21Z
Modified
2026-09-17T20:45:06Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
HAPI FHIR: SHCParser DEFLATE infinite loop causes denial of service
Details

Summary

A 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.

Details

The vulnerable code is in org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java.

decodeJWT() inflates the JWT payload when the header contains "zip":"DEF":

// SHCParser.java:300-302
if ("DEF".equals(res.header.asString("zip"))) {
  payloadJson = inflate(payloadJson);
}

inflate() loops only on !inflater.finished() and does not check inflater.needsInput(), inflater.needsDictionary(), or zero-progress output:

// SHCParser.java:455-468
while (!inflater.finished()) {
  final int count = inflater.inflate(buffer);
  outputStream.write(buffer, 0, count);
}

For 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.

The validator reaches this path during SHC validation and during file-format detection for SHC-looking input (ResourceChecker.java:115-118).

PoC

Compile the project, then run a minimal local harness that calls:

SHCParser.inflate(new byte[0]);

This never returns. Local verification:

timeout 3s java -cp ... VerifyDoSFindings shcHang
echo $?
# 124 = timeout killed the hung process

A JWT PoC uses:

  • header: Base64URL({"zip":"DEF"})
  • payload: empty or truncated raw DEFLATE bytes
  • signature: arbitrary

Submit the resulting token as SHC content, for example via a .shc file or content beginning with shc:/ that reaches the validator's SHC detection path.

Impact

This is a denial-of-service vulnerability. A single malformed SHC validation request can consume a worker thread indefinitely. In services that validate uploaded SHC content, a small number of concurrent malformed requests can exhaust all validation workers.

Credits

  • Thai Son Dinh from VinSOC Labs (R&D)
Database specific 
{
    "cwe_ids": [
        "CWE-20",
        "CWE-400",
        "CWE-835"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-17T20:32:21Z",
    "nvd_published_at": "2026-09-16T19:17:44Z",
    "severity": "HIGH"
}
References

Affected packages

Maven
ca.uhn.hapi.fhir:org.hl7.fhir.r5

Package

Name
ca.uhn.hapi.fhir:org.hl7.fhir.r5
View open source insights on deps.dev
Purl
pkg:maven/ca.uhn.hapi.fhir/org.hl7.fhir.r5

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.9.12

Affected versions

0.*
0.0.1
0.0.2
0.0.14
0.1.18
1.*
1.0.0
1.1.67
4.*
4.0.0
4.0.1
4.0.2
4.0.3
4.1.0
4.2.0
5.*
5.0.0
5.0.7
5.0.8
5.0.9
5.0.10
5.0.11
5.0.12
5.0.13
5.0.14
5.0.15
5.0.16
5.0.17
5.0.18
5.0.19
5.0.20
5.0.21
5.0.22
5.1.0
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
5.1.8
5.1.9
5.1.10
5.1.11
5.1.12
5.1.13
5.1.14
5.1.15
5.1.16
5.1.17
5.1.18
5.1.19
5.1.20
5.1.21
5.1.22
5.2.0
5.2.1
5.2.3
5.2.4
5.2.5
5.2.7
5.2.8
5.2.9
5.2.10
5.2.11
5.2.12
5.2.13
5.2.16
5.2.18
5.2.19
5.2.20
5.3.0
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.3.7
5.3.8
5.3.9
5.3.10
5.3.11
5.3.12
5.3.14
5.4.0
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.4.8
5.4.9
5.4.10
5.4.11
5.4.12
5.5.1
5.5.2
5.5.3
5.5.4
5.5.6
5.5.7
5.5.8
5.5.9
5.5.10
5.5.11
5.5.12
5.5.13
5.5.14
5.5.15
5.5.16
5.6.0
5.6.1
5.6.2
5.6.3
5.6.4
5.6.5
5.6.6
5.6.7
5.6.9
5.6.12
5.6.13
5.6.15
5.6.17
5.6.18
5.6.19
5.6.20
5.6.21
5.6.22
5.6.23
5.6.24
5.6.25
5.6.26
5.6.27
5.6.28
5.6.29
5.6.30
5.6.31
5.6.32
5.6.33
5.6.34
5.6.35
5.6.36
5.6.37
5.6.38
5.6.39
5.6.40
5.6.41
5.6.42
5.6.43
5.6.44
5.6.45
5.6.46
5.6.47
5.6.48
5.6.50
5.6.51
5.6.52
5.6.53
5.6.54
5.6.55
5.6.56
5.6.57
5.6.58
5.6.59
5.6.60
5.6.61
5.6.62
5.6.63
5.6.64
5.6.65
5.6.66
5.6.67
5.6.68
5.6.69
5.6.70
5.6.71
5.6.72
5.6.73
5.6.74
5.6.75
5.6.76
5.6.77
5.6.78
5.6.79
5.6.80
5.6.81
5.6.82
5.6.83
5.6.84
5.6.85
5.6.86
5.6.87
5.6.88
5.6.89
5.6.90
5.6.91
5.6.92
5.6.93
5.6.94
5.6.95
5.6.96
5.6.97
5.6.98
5.6.99
5.6.100
5.6.101
5.6.102
5.6.103
5.6.104
5.6.105
5.6.106
5.6.107
5.6.108
5.6.109
5.6.110
5.6.111
5.6.112
5.6.113
5.6.114
5.6.115
5.6.116
5.6.117
5.6.881
5.6.971
6.*
6.0.0
6.0.1
6.0.2
6.0.3
6.0.4
6.0.5
6.0.6
6.0.7
6.0.8
6.0.9
6.0.10
6.0.11
6.0.12
6.0.13
6.0.14
6.0.15
6.0.16
6.0.17
6.0.18
6.0.19
6.0.20
6.0.21
6.0.22
6.0.22.1
6.0.22.2
6.0.23
6.0.24
6.0.25
6.1.0
6.1.1
6.1.2
6.1.2.1
6.1.2.2
6.1.3
6.1.4
6.1.5
6.1.6
6.1.7
6.1.8
6.1.9
6.1.10
6.1.11
6.1.12
6.1.13
6.1.14
6.1.15
6.1.16
6.2.0
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.6.1
6.2.7
6.2.8
6.2.9
6.2.10
6.2.11
6.2.12
6.2.13
6.2.14
6.2.15
6.3.0
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.7
6.3.8
6.3.9
6.3.10
6.3.11
6.3.12
6.3.13
6.3.14
6.3.15
6.3.16
6.3.17
6.3.18
6.3.19
6.3.20
6.3.21
6.3.22
6.3.23
6.3.24
6.3.25
6.3.26
6.3.27
6.3.28
6.3.29
6.3.30
6.3.31
6.3.32
6.4.0
6.4.1
6.4.2
6.4.3
6.4.4
6.5.0
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
6.5.6
6.5.7
6.5.8
6.5.9
6.5.10
6.5.11
6.5.12
6.5.13
6.5.14
6.5.15
6.5.16
6.5.17
6.5.18
6.5.18.1
6.5.19
6.5.20
6.5.21
6.5.22
6.5.23
6.5.24
6.5.25
6.5.26
6.5.27
6.5.28
6.6.0
6.6.1
6.6.2
6.6.3
6.6.4
6.6.5
6.6.6
6.6.7
6.7.0
6.7.1
6.7.2
6.7.3
6.7.4
6.7.5
6.7.6
6.7.7
6.7.8
6.7.9
6.7.10
6.7.11
6.8.0
6.8.1
6.8.2
6.9.0
6.9.1
6.9.2
6.9.3
6.9.4
6.9.4.1
6.9.4.2
6.9.5
6.9.6
6.9.7
6.9.8
6.9.9
6.9.10
6.9.11

Database specific

last_known_affected_version_range 
"<= 6.9.11"
source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-gq9c-wmrm-5hvr/GHSA-gq9c-wmrm-5hvr.json"
ca.uhn.hapi.fhir:org.hl7.fhir.validation

Package

Name
ca.uhn.hapi.fhir:org.hl7.fhir.validation
View open source insights on deps.dev
Purl
pkg:maven/ca.uhn.hapi.fhir/org.hl7.fhir.validation

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.9.12

Affected versions

0.*
0.0.1
0.0.2
0.0.14
0.1.18
1.*
1.0.0
1.1.67
4.*
4.0.0
4.0.1
4.0.2
4.0.3
4.1.0
4.2.0
5.*
5.0.0
5.0.7
5.0.8
5.0.9
5.0.10
5.0.11
5.0.12
5.0.13
5.0.14
5.0.15
5.0.16
5.0.17
5.0.18
5.0.19
5.0.20
5.0.21
5.0.22
5.1.0
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
5.1.8
5.1.9
5.1.10
5.1.11
5.1.12
5.1.13
5.1.14
5.1.15
5.1.16
5.1.17
5.1.18
5.1.19
5.1.20
5.1.21
5.1.22
5.2.0
5.2.1
5.2.3
5.2.4
5.2.5
5.2.7
5.2.8
5.2.9
5.2.10
5.2.11
5.2.12
5.2.13
5.2.16
5.2.18
5.2.19
5.2.20
5.3.0
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.3.7
5.3.8
5.3.9
5.3.10
5.3.11
5.3.12
5.3.14
5.4.0
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.4.8
5.4.9
5.4.10
5.4.11
5.4.12
5.5.1
5.5.2
5.5.3
5.5.4
5.5.6
5.5.7
5.5.8
5.5.9
5.5.10
5.5.11
5.5.12
5.5.13
5.5.14
5.5.15
5.5.16
5.6.0
5.6.1
5.6.2
5.6.3
5.6.4
5.6.5
5.6.6
5.6.7
5.6.9
5.6.12
5.6.13
5.6.15
5.6.17
5.6.18
5.6.19
5.6.20
5.6.21
5.6.22
5.6.23
5.6.24
5.6.25
5.6.26
5.6.27
5.6.28
5.6.29
5.6.30
5.6.31
5.6.32
5.6.33
5.6.34
5.6.35
5.6.36
5.6.37
5.6.38
5.6.39
5.6.40
5.6.41
5.6.42
5.6.43
5.6.44
5.6.45
5.6.46
5.6.47
5.6.48
5.6.50
5.6.51
5.6.52
5.6.53
5.6.54
5.6.55
5.6.56
5.6.57
5.6.58
5.6.59
5.6.60
5.6.61
5.6.62
5.6.63
5.6.64
5.6.65
5.6.66
5.6.67
5.6.68
5.6.69
5.6.70
5.6.71
5.6.72
5.6.73
5.6.74
5.6.75
5.6.76
5.6.77
5.6.78
5.6.79
5.6.80
5.6.81
5.6.82
5.6.83
5.6.84
5.6.85
5.6.86
5.6.87
5.6.88
5.6.89
5.6.90
5.6.91
5.6.92
5.6.93
5.6.94
5.6.95
5.6.96
5.6.97
5.6.98
5.6.99
5.6.100
5.6.101
5.6.102
5.6.103
5.6.104
5.6.105
5.6.106
5.6.107
5.6.108
5.6.109
5.6.110
5.6.111
5.6.112
5.6.113
5.6.114
5.6.115
5.6.116
5.6.117
5.6.881
5.6.971
6.*
6.0.0
6.0.1
6.0.2
6.0.3
6.0.4
6.0.5
6.0.6
6.0.7
6.0.8
6.0.9
6.0.10
6.0.11
6.0.12
6.0.13
6.0.14
6.0.15
6.0.16
6.0.17
6.0.18
6.0.19
6.0.20
6.0.21
6.0.22
6.0.22.1
6.0.22.2
6.0.23
6.0.24
6.0.25
6.1.0
6.1.1
6.1.2
6.1.2.1
6.1.2.2
6.1.3
6.1.4
6.1.5
6.1.6
6.1.7
6.1.8
6.1.9
6.1.10
6.1.11
6.1.12
6.1.13
6.1.14
6.1.15
6.1.16
6.2.0
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.6.1
6.2.7
6.2.8
6.2.9
6.2.10
6.2.11
6.2.12
6.2.13
6.2.14
6.2.15
6.3.0
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.7
6.3.8
6.3.9
6.3.10
6.3.11
6.3.12
6.3.13
6.3.14
6.3.15
6.3.16
6.3.17
6.3.18
6.3.19
6.3.20
6.3.21
6.3.22
6.3.23
6.3.24
6.3.25
6.3.26
6.3.27
6.3.28
6.3.29
6.3.30
6.3.31
6.3.32
6.4.0
6.4.1
6.4.2
6.4.3
6.4.4
6.5.0
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
6.5.6
6.5.7
6.5.8
6.5.9
6.5.10
6.5.11
6.5.12
6.5.13
6.5.14
6.5.15
6.5.16
6.5.17
6.5.18
6.5.18.1
6.5.19
6.5.20
6.5.21
6.5.22
6.5.23
6.5.24
6.5.25
6.5.26
6.5.27
6.5.28
6.6.0
6.6.1
6.6.2
6.6.3
6.6.4
6.6.5
6.6.6
6.6.7
6.7.0
6.7.1
6.7.2
6.7.3
6.7.4
6.7.5
6.7.6
6.7.7
6.7.8
6.7.9
6.7.10
6.7.11
6.8.0
6.8.1
6.8.2
6.9.0
6.9.1
6.9.2
6.9.3
6.9.4
6.9.4.1
6.9.4.2
6.9.5
6.9.6
6.9.7
6.9.8
6.9.9
6.9.10
6.9.11

Database specific

last_known_affected_version_range 
"<= 6.9.11"
source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-gq9c-wmrm-5hvr/GHSA-gq9c-wmrm-5hvr.json"
ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli

Package

Name
ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli
View open source insights on deps.dev
Purl
pkg:maven/ca.uhn.hapi.fhir/org.hl7.fhir.validation.cli

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.9.12

Affected versions

4.*
4.0.0
4.0.1
4.0.2
4.0.3
4.1.0
4.2.0
5.*
5.0.0

Database specific

last_known_affected_version_range 
"<= 6.9.11"
source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-gq9c-wmrm-5hvr/GHSA-gq9c-wmrm-5hvr.json"