{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33938","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-03-24T19:50:52.103Z","datePublished":"2026-03-27T21:05:42.485Z","dateUpdated":"2026-07-02T12:05:17.351Z"},"containers":{"cna":{"title":"Handlebars.js has JavaScript Injection via AST Type Confusion by tampering @partial-block","problemTypes":[{"descriptions":[{"cweId":"CWE-94","lang":"en","description":"CWE-94: Improper Control of Generation of Code ('Code Injection')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-843","lang":"en","description":"CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/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-3mfm-83xf-c92r","tags":["x_refsource_CONFIRM"],"url":"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r"},{"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":"2026-03-27T21:05:42.485Z"},"descriptions":[{"lang":"en","value":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the `@partial-block` special variable is stored in the template data context and is reachable and mutable from within a template via helpers that accept arbitrary objects. When a helper overwrites `@partial-block` with a crafted Handlebars AST, a subsequent invocation of `{{> @partial-block}}` compiles and executes that AST, enabling arbitrary JavaScript execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build (`require('handlebars/runtime')`). The `compile()` method is  absent, eliminating the vulnerable fallback path. Second, audit registered helpers for any that write arbitrary values to context objects. Helpers  should treat context data as read-only. Third, avoid registering helpers from third-party packages (such as `handlebars-helpers`) in  contexts where templates or context data can be influenced by untrusted input."}],"source":{"advisory":"GHSA-3mfm-83xf-c92r","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-31T00:00:00+00:00","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-33938"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-01T03:55:42.796Z"}},{"affected":[{"cpes":["cpe:/a:redhat:cluster_observability_operator:1.5::el9"],"defaultStatus":"affected","product":"Cluster Observability Operator 1.5.0","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:openshift_devspaces:3.27::el9"],"defaultStatus":"affected","product":"Red Hat OpenShift Dev Spaces 3.27","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:logging:5"],"defaultStatus":"affected","product":"Logging Subsystem for Red Hat OpenShift","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"affected","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:cryostat:4"],"defaultStatus":"unaffected","product":"Cryostat 4","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_data_grid:8"],"defaultStatus":"unaffected","product":"Red Hat Data Grid 8","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:10"],"defaultStatus":"unaffected","product":"Red Hat Enterprise Linux 10","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:7"],"defaultStatus":"unaffected","product":"Red Hat Enterprise Linux 7","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:9"],"defaultStatus":"unaffected","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:openshift_ai"],"defaultStatus":"unaffected","product":"Red Hat OpenShift AI (RHOAI)","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_enterprise_bpms_platform:7"],"defaultStatus":"unaffected","product":"Red Hat Process Automation 7","vendor":"Red Hat"}],"datePublic":"2026-03-27T21:05:42.485Z","descriptions":[{"lang":"en","value":"A flaw was found in Handlebars. A remote attacker can exploit this vulnerability by manipulating the `@partial-block` special variable within the template data context. By overwriting `@partial-block` with a specially crafted Abstract Syntax Tree (AST) through a helper, a subsequent invocation of `{{> @partial-block}}` will compile and execute the malicious AST. This enables arbitrary JavaScript execution on the server, leading to potential compromise of the system."}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Important"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-917","description":"Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')","lang":"en","type":"CWE"}]}],"references":[{"tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-33938"},{"name":"RHBZ#2452525","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2452525"},{"tags":["x_sadp-csaf-vex"],"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33938.json"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:34342"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:10175"}],"solutions":[{"lang":"en","value":"RHSA-2026:34342: Cluster Observability Operator 1.5.0"},{"lang":"en","value":"RHSA-2026:10175: Red Hat OpenShift Dev Spaces 3.27"}],"timeline":[{"lang":"en","time":"2026-03-27T22:02:58.504Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-03-27T21:05:42.485Z","value":"Made public."}],"title":"handlebars: Handlebars: Arbitrary code execution via @partial-block overwrite","workarounds":[{"lang":"en","value":"Applications using Handlebars should implement the runtime-only build (`require('handlebars/runtime')`) to prevent exploitation, as this build lacks the vulnerable `compile()` method. Additionally, review all registered helpers to ensure they do not write arbitrary values to context objects, and avoid using third-party helpers in contexts exposed to untrusted input."}],"x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"},"providerMetadata":{"orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","shortName":"redhat-SADP","dateUpdated":"2026-07-02T12:05:17.351Z"}}]}}