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MediumFix available

Keycloak: keycloak: denial of service due to excessive samlrequest decompression

Type: advisorySources: OSV

A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.

Products
keycloak
Affected versions
Not specified
Fixed versions
26.4.10
CVEs
CVE-2026-2575
Confirmed fixed CVEs
Not specified
Updated in this feed
28 Oct 2026, 04:20 UTC · Revision 1

Source evidence

Keycloak: keycloak: denial of service due to excessive samlrequest decompression

core-osv · Original source

Published 25 Aug 2026, 11:42 UTC

A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.

osv:BIT-keycloak-2026-2575

keycloak

Fixed versions: 26.4.10

Complete source record
{
  "id": "2b43d581d27ee38a1b6f54c588044cf056f4c21171a47b5bf8011c5de3b8fd32",
  "url": "https://osv.dev/vulnerability/BIT-keycloak-2026-2575",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Keycloak: keycloak: denial of service due to excessive samlrequest decompression",
    "summary": "A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.",
    "evidence": "osv:BIT-keycloak-2026-2575",
    "products": [
      {
        "name": {
          "value": "keycloak",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "26.4.10",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-keycloak-2026-2575",
      "aliases": [
        "BIT-keycloak-2026-2575",
        "CVE-2026-2575",
        "GHSA-xv6h-r36f-3gp5"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "26.4.0"
                },
                {
                  "fixed": "26.4.10"
                }
              ]
            }
          ],
          "package": {
            "name": "keycloak",
            "purl": "pkg:bitnami/keycloak",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/keycloak/BIT-keycloak-2026-2575.json"
          }
        }
      ],
      "modified": "2026-10-07T14:30:10.814362493Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/errata/RHSA-2026:3947",
        "https://access.redhat.com/errata/RHSA-2026:3948",
        "https://access.redhat.com/security/cve/CVE-2026-2575",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2440149",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-2575",
        "https://access.redhat.com/errata/RHSA-2026:76128",
        "https://access.redhat.com/errata/RHSA-2026:76129",
        "https://access.redhat.com/errata/RHSA-2026:76130",
        "https://access.redhat.com/errata/RHSA-2026:76132",
        "https://access.redhat.com/errata/RHSA-2026:76134"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*",
          "cpe:2.3:a:keycloak:keycloak:*:*:*:*:*:*:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-2575",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 95111,
  "published_at": "2026-08-25T11:42:11.943+00:00"
}