{
  "threat_severity" : "Important",
  "public_date" : "2026-04-17T21:53:47Z",
  "bugzilla" : {
    "description" : "thymeleaf: Thymeleaf: Server-Side Template Injection via security bypass in expression execution",
    "id" : "2459344",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2459344"
  },
  "cvss3" : {
    "cvss3_base_score" : "8.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-917",
  "details" : [ "Thymeleaf is a server-side Java template engine for web and standalone environments. Versions 3.1.3.RELEASE and prior contain a security bypass vulnerability in the expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly restrict the scope of accessible objects, allowing specific potentially sensitive objects to be reached from within a template. If an application developer passes unvalidated user input directly to the template engine, an unauthenticated remote attacker can bypass the library's protections to achieve Server-Side Template Injection (SSTI). This issue has ben fixed in version 3.1.4.RELEASE.", "A flaw was found in Thymeleaf, a server-side Java template engine. An unauthenticated remote attacker can exploit a security bypass vulnerability in the expression execution mechanisms. By providing unvalidated user input directly to the template engine, the attacker can bypass the library's protections, leading to Server-Side Template Injection (SSTI). This allows access to potentially sensitive objects from within a template." ],
  "affected_release" : [ {
    "product_name" : "Red Hat OpenShift Dev Spaces 3.28",
    "release_date" : "2026-05-28T00:00:00Z",
    "advisory" : "RHSA-2026:21772",
    "cpe" : "cpe:/a:redhat:openshift_devspaces:3.28::el9",
    "package" : "devspaces/openvsx-rhel9:1779528224"
  }, {
    "product_name" : "Red Hat OpenShift Dev Spaces 3.28",
    "release_date" : "2026-05-28T00:00:00Z",
    "advisory" : "RHSA-2026:21772",
    "cpe" : "cpe:/a:redhat:openshift_devspaces:3.28::el9",
    "package" : "devspaces/pluginregistry-rhel9:1779359423"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat build of Apache Camel for Spring Boot 4",
    "fix_state" : "Not affected",
    "package_name" : "camel-thymeleaf",
    "cpe" : "cpe:/a:redhat:camel_spring_boot:4"
  }, {
    "product_name" : "Red Hat build of Apache Camel for Spring Boot 4",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:camel_spring_boot:4"
  }, {
    "product_name" : "Red Hat Fuse 7",
    "fix_state" : "Will not fix",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_fuse:7"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 7",
    "fix_state" : "Not affected",
    "package_name" : "smallrye-mutiny-vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:7"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 7",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:7"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 7",
    "fix_state" : "Not affected",
    "package_name" : "vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:7"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 8",
    "fix_state" : "Not affected",
    "package_name" : "smallrye-mutiny-vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:8"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 8",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:8"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform 8",
    "fix_state" : "Not affected",
    "package_name" : "vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jboss_enterprise_application_platform:8"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "smallrye-mutiny-vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "spring-boot-starter-thymeleaf",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf-extras-java8time",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "thymeleaf-spring5",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "fix_state" : "Not affected",
    "package_name" : "vertx-web-templ-thymeleaf",
    "cpe" : "cpe:/a:redhat:jbosseapxp"
  }, {
    "product_name" : "Red Hat Single Sign-On 7",
    "fix_state" : "Will not fix",
    "package_name" : "spring-boot-starter-thymeleaf",
    "cpe" : "cpe:/a:redhat:red_hat_single_sign_on:7"
  }, {
    "product_name" : "Red Hat Single Sign-On 7",
    "fix_state" : "Will not fix",
    "package_name" : "thymeleaf",
    "cpe" : "cpe:/a:redhat:red_hat_single_sign_on:7"
  }, {
    "product_name" : "Red Hat Single Sign-On 7",
    "fix_state" : "Will not fix",
    "package_name" : "thymeleaf-extras-java8time",
    "cpe" : "cpe:/a:redhat:red_hat_single_sign_on:7"
  }, {
    "product_name" : "Red Hat Single Sign-On 7",
    "fix_state" : "Will not fix",
    "package_name" : "thymeleaf-spring5",
    "cpe" : "cpe:/a:redhat:red_hat_single_sign_on:7"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-40477\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-40477\nhttps://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-r4v4-5mwr-2fwr" ],
  "name" : "CVE-2026-40477",
  "mitigation" : {
    "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.",
    "lang" : "en:us"
  },
  "csaw" : false
}