CVE-2026-18206 (GCVE-0-2026-18206)
Vulnerability from cvelistv5
Published
2026-07-31 07:08
Modified
2026-07-31 10:59
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-20 - Improper Input Validation
Summary
A flaw was found in the keycloak-services component of Keycloak, which provides identity and access management services. The issue occurs when a realm administrator uses a wildcard domain (like *.example.com) to restrict which hosts can register or update clients. Due to improper validation, the system accepts any hostname that ends with the specified domain suffix, even if it is not a legitimate subdomain. An attacker who can control the reverse DNS of their connection can bypass these host-based restrictions, potentially allowing unauthorized client modifications.
References
| URL | Tags | |||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
Impacted products
| Vendor | Product | Version | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Red Hat | Red Hat Build of Keycloak |
cpe:/a:redhat:build_keycloak: |
|||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-18206",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-31T10:57:44.771477Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-31T10:59:36.218Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:"
],
"defaultStatus": "affected",
"packageName": "keycloak-services",
"product": "Red Hat Build of Keycloak",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:"
],
"defaultStatus": "affected",
"packageName": "rhbk-keycloak-rhel9/rhbk-keycloak-rhel9",
"product": "Red Hat Build of Keycloak",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:"
],
"defaultStatus": "affected",
"packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9",
"product": "Red Hat Build of Keycloak",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:jboss_data_grid:8"
],
"defaultStatus": "unaffected",
"packageName": "keycloak-services",
"product": "Red Hat Data Grid 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jbosseapxp"
],
"defaultStatus": "unaffected",
"packageName": "keycloak-services",
"product": "Red Hat JBoss Enterprise Application Platform Expansion Pack",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:red_hat_single_sign_on:7"
],
"defaultStatus": "unaffected",
"packageName": "keycloak-services",
"product": "Red Hat Single Sign-On 7",
"vendor": "Red Hat"
}
],
"credits": [
{
"lang": "en",
"value": "Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue."
}
],
"datePublic": "2026-07-28T13:36:46.000Z",
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in the keycloak-services component of Keycloak, which provides identity and access management services. The issue occurs when a realm administrator uses a wildcard domain (like *.example.com) to restrict which hosts can register or update clients. Due to improper validation, the system accepts any hostname that ends with the specified domain suffix, even if it is not a legitimate subdomain. An attacker who can control the reverse DNS of their connection can bypass these host-based restrictions, potentially allowing unauthorized client modifications."
}
],
"metrics": [
{
"other": {
"content": {
"namespace": "https://access.redhat.com/security/updates/classification/",
"value": "Low"
},
"type": "Red Hat severity rating"
}
},
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 3.7,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-20",
"description": "Improper Input Validation",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-31T07:08:29.626Z",
"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
"shortName": "redhat"
},
"references": [
{
"tags": [
"vdb-entry",
"x_refsource_REDHAT"
],
"url": "https://access.redhat.com/security/cve/CVE-2026-18206"
},
{
"name": "RHBZ#2508292",
"tags": [
"issue-tracking",
"x_refsource_REDHAT"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2508292"
}
],
"timeline": [
{
"lang": "en",
"time": "2026-07-28T13:36:46.000Z",
"value": "Reported to Red Hat."
},
{
"lang": "en",
"time": "2026-07-28T13:36:46.000Z",
"value": "Made public."
}
],
"title": "Keycloak-services: keycloak-services: client policy source-host wildcard domain matching bypass",
"workarounds": [
{
"lang": "en",
"value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
},
"x_redhatCweChain": "CWE-20: Improper Input Validation"
}
},
"cveMetadata": {
"assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
"assignerShortName": "redhat",
"cveId": "CVE-2026-18206",
"datePublished": "2026-07-31T07:08:29.626Z",
"dateReserved": "2026-07-29T07:56:25.314Z",
"dateUpdated": "2026-07-31T10:59:36.218Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-18206\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-31T10:57:44.771477Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-31T10:59:21.865Z\"}}], \"cna\": {\"title\": \"Keycloak-services: keycloak-services: client policy source-host wildcard domain matching bypass\", \"credits\": [{\"lang\": \"en\", \"value\": \"Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue.\"}], \"metrics\": [{\"other\": {\"type\": \"Red Hat severity rating\", \"content\": {\"value\": \"Low\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}}}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 3.7, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"cpes\": [\"cpe:/a:redhat:build_keycloak:\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Build of Keycloak\", \"packageName\": \"keycloak-services\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:build_keycloak:\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Build of Keycloak\", \"packageName\": \"rhbk-keycloak-rhel9/rhbk-keycloak-rhel9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:build_keycloak:\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Build of Keycloak\", \"packageName\": \"rhbk-openshift-rhel9/rhbk-openshift-rhel9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:jboss_data_grid:8\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Data Grid 8\", \"packageName\": \"keycloak-services\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/a:redhat:jbosseapxp\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat JBoss Enterprise Application Platform Expansion Pack\", \"packageName\": \"keycloak-services\", \"collectionURL\": \"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/a:redhat:red_hat_single_sign_on:7\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Single Sign-On 7\", \"packageName\": \"keycloak-services\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-07-28T13:36:46.000Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-07-28T13:36:46.000Z\", \"value\": \"Made public.\"}], \"datePublic\": \"2026-07-28T13:36:46.000Z\", \"references\": [{\"url\": \"https://access.redhat.com/security/cve/CVE-2026-18206\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2508292\", \"name\": \"RHBZ#2508292\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.\"}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"A flaw was found in the keycloak-services component of Keycloak, which provides identity and access management services. The issue occurs when a realm administrator uses a wildcard domain (like *.example.com) to restrict which hosts can register or update clients. Due to improper validation, the system accepts any hostname that ends with the specified domain suffix, even if it is not a legitimate subdomain. An attacker who can control the reverse DNS of their connection can bypass these host-based restrictions, potentially allowing unauthorized client modifications.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-20\", \"description\": \"Improper Input Validation\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-07-31T07:08:29.626Z\"}, \"x_redhatCweChain\": \"CWE-20: Improper Input Validation\"}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-18206\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-31T10:59:36.218Z\", \"dateReserved\": \"2026-07-29T07:56:25.314Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-07-31T07:08:29.626Z\", \"assignerShortName\": \"redhat\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…