{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33937", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-24T19:50:52.103Z", "datePublished": "2026-03-27T21:03:46.748Z", "dateUpdated": "2026-04-01T03:55:43.931Z"}, "containers": {"cna": {"title": "Handlebars.js has JavaScript Injection via AST Type Confusion", "problemTypes": [{"descriptions": [{"cweId": "CWE-843", "lang": "en", "description": "CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-94", "lang": "en", "description": "CWE-94: Improper Control of Generation of Code ('Code Injection')", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q"}, {"name": "https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2", "tags": ["x_refsource_MISC"], "url": "https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2"}, {"name": "https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9", "tags": ["x_refsource_MISC"], "url": "https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"}], "affected": [{"vendor": "handlebars-lang", "product": "handlebars.js", "versions": [{"version": ">= 4.0.0, < 4.7.9", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-27T21:03:46.748Z"}, "descriptions": [{"lang": "en", "value": "Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable."}], "source": {"advisory": "GHSA-2w6w-674q-4c4q", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-31T00:00:00+00:00", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3", "id": "CVE-2026-33937"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-01T03:55:43.931Z"}}]}}

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{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "A9D1F9A7-8359-4C3F-9932-4A085094F388", "versionEndExcluding": "4.7.9", "versionStartIncluding": "4.0.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable."}], "id": "CVE-2026-33937", "lastModified": "2026-03-31T17:49:05.807", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-27T21:17:27.417", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"}, {"source": "security-advisories@github.com", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-94"}, {"lang": "en", "value": "CWE-843"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "handlebars.js: Handlebars: Remote Code Execution via crafted Abstract Syntax Tree object in compile()", "id": "2452523", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452523"}, "csaw": false, "cvss3": {"cvss3_base_score": "9.8", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-94", "details": ["A flaw was found in Handlebars. An attacker can exploit this by supplying a crafted Abstract Syntax Tree (AST) object to the `Handlebars.compile()` function. This allows the injection and execution of arbitrary JavaScript code due to improper sanitization of the `value` field in `NumberLiteral` AST nodes. This vulnerability can lead to Remote Code Execution (RCE) on the server."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, ensure that any input provided to the `Handlebars.compile()` function is strictly validated to be a string type, preventing the injection of crafted Abstract Syntax Tree (AST) objects. Additionally, for deployments where templates are pre-compiled at build time, consider utilizing the Handlebars runtime-only build (`handlebars/runtime`). This build variant does not include the `compile()` function, thereby eliminating the attack vector. If the application is a service, a restart may be required for the changes to take effect."}, "name": "CVE-2026-33937", "package_state": [{"cpe": "cpe:/a:redhat:cryostat:4", "fix_state": "Affected", "package_name": "handlebars", "product_name": "Cryostat 4"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/elasticsearch6-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/elasticsearch-operator-bundle", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/elasticsearch-proxy-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/elasticsearch-rhel9-operator", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/kibana6-rhel8", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/logging-curator5-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:jboss_data_grid:8", "fix_state": "Affected", "package_name": "handlebars", "product_name": "Red Hat Data Grid 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "389-ds:1.4/389-ds-base", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "grafana", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "mozjs60", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/code-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}, {"cpe": "cpe:/a:redhat:jboss_enterprise_bpms_platform:7", "fix_state": "Affected", "package_name": "handlebars", "product_name": "Red Hat Process Automation 7"}], "public_date": "2026-03-27T21:03:46Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-33937\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-33937\nhttps://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2\nhttps://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9\nhttps://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q"], "statement": "This is an Important vulnerability in Handlebars that allows for Remote Code Execution. The flaw occurs when the `Handlebars.compile()` function processes a specially crafted Abstract Syntax Tree (AST) object, leading to the injection and execution of arbitrary JavaScript code. Red Hat products utilizing Handlebars are affected if they process untrusted input through the `compile()` function.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.0.0,4.7.9)"}}], "enrichment": {"confidence": 81.0, "confidence_source": "matching", "scores": [{"score": 81.0, "source": "matching"}]}, "original": {"product": "handlebars.js", "source": "cna", "vendor": "handlebars-lang"}, "product": "handlebars", "vendor": "handlebarsjs"}], "analysis": {"en": {"generated_at": "2026-03-31T19:42:37.310917+00:00", "value": {"mitigation_remediation": ["Upgrade to Handlebars 4.7.9 or newer to patch the vulnerability.", "If an upgrade is not immediately possible, validate that the argument to Handlebars.compile is a string; reject or reject objects that could be parsed as an AST.", "For pre\u2011compiled templates, use the runtime\u2011only build (handlebars/runtime), which removes the compile function from the server environment.", "As a temporary measure, disable any functionality that accepts untrusted template data from external users."], "summary": {"action": "Immediate Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "The affected package is Handlebars.js, maintained by the handlebars\u2011lang project. All releases from 4.0.0 up to, but not including, 4.7.9 are vulnerable. The issue applies to environments that use the Node.js runtime, as indicated by the CPE string. Version 4.7.9 and later contain a fix that removes the ability to pass an AST directly to compile and properly sanitizes numeric values.", "description_and_impact": "Handlebars, a templating engine widely used in web applications, has a flaw in versions 4.0.0 through 4.7.8. The library\u2019s compile function accepts a pre\u2011parsed abstract syntax tree (AST) as well as a plain text template. In a NumberLiteral node the numeric value is inserted into the generated JavaScript output without quotations or any form of sanitization. An attacker who can supply a crafted AST to compile can therefore inject and execute arbitrary JavaScript when the template is rendered. This allows remote code execution on the server with the privileges of the process running Handlebars. The weakness is reflected in CWE\u2011843 (Incorrect Type Conversion) and CWE\u201194 (Code Injection).", "risk_and_exploitability": "The vulnerability carries a CVSS score of 9.8, indicating critical severity. The EPSS score is listed as less than 1\u202f%, suggesting that few attacks have been observed or expected. It is not currently included in the CISA KEV catalog. Exploitation requires an attacker to supply a malicious AST to the compile function, which may be feasible through application input that is passed directly to compile or via an API that accepts template data without validation. When successful, the attacker can run arbitrary JavaScript with the permission of the hosting process."}}}}, "created": "2026-03-29T20:29:51.617370+00:00", "updated": "2026-03-31T20:00:41.763847+00:00", "vendors": ["handlebarsjs", "handlebarsjs$PRODUCT$handlebars"]}