FKIE_CVE-2026-18212
Vulnerability from fkie_nvd - Published: 2026-09-16 15:17 - Updated: 2026-09-16 19:42
Severity
Summary
A flaw was found in the SAML Redirect Binding implementation of Keycloak, an open-source identity and access management solution. The issue occurs because the custom DEFLATE compression and decompression helpers fail to release native zlib memory after use. An unauthenticated attacker can exploit this by sending repeated malformed SAML requests, leading to native memory exhaustion and a denial of service.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.4::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-operator-bundle",
"product": "Red Hat build of Keycloak 26.4",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.4.16-2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.4::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-rhel9",
"product": "Red Hat build of Keycloak 26.4",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.4-26",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.4::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-rhel9-operator",
"product": "Red Hat build of Keycloak 26.4",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.4-26",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.4::el9"
],
"defaultStatus": "unaffected",
"packageName": "keycloak-services",
"product": "Red Hat build of Keycloak 26.4.16",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.4::el9"
],
"defaultStatus": "unaffected",
"packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9",
"product": "Red Hat build of Keycloak 26.4.16",
"vendor": "Red Hat"
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-operator-bundle",
"product": "Red Hat build of Keycloak 26.6",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.6.7-3",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-rhel9",
"product": "Red Hat build of Keycloak 26.6",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.6-20",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "affected",
"packageName": "rhbk/keycloak-rhel9-operator",
"product": "Red Hat build of Keycloak 26.6",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "26.6-20",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "unaffected",
"packageName": "keycloak-services",
"product": "Red Hat build of Keycloak 26.6.7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "unaffected",
"packageName": "rhbk-keycloak-rhel9/rhbk-keycloak-rhel9",
"product": "Red Hat build of Keycloak 26.6.7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:build_keycloak:26.6::el9"
],
"defaultStatus": "unaffected",
"packageName": "rhbk-openshift-rhel9/rhbk-openshift-rhel9",
"product": "Red Hat build of Keycloak 26.6.7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:jboss_data_grid:8"
],
"defaultStatus": "affected",
"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": "affected",
"packageName": "keycloak-services",
"product": "Red Hat Single Sign-On 7",
"vendor": "Red Hat"
}
],
"source": "secalert@redhat.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in the SAML Redirect Binding implementation of Keycloak, an open-source identity and access management solution. The issue occurs because the custom DEFLATE compression and decompression helpers fail to release native zlib memory after use. An unauthenticated attacker can exploit this by sending repeated malformed SAML requests, leading to native memory exhaustion and a denial of service."
}
],
"id": "CVE-2026-18212",
"lastModified": "2026-09-16T19:42:43.623",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "secalert@redhat.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-18212",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-16T18:25:11.882582Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-16T15:17:33.257",
"references": [
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:68276"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:68277"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:68278"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/errata/RHSA-2026:68280"
},
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/security/cve/CVE-2026-18212"
},
{
"source": "secalert@redhat.com",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2508307"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-401"
}
],
"source": "secalert@redhat.com",
"type": "Secondary"
}
]
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…