8.1
HIGH
CVSS 3.1
CVE-2026-33938
Handlebars.js has JavaScript Injection via AST Type Confusion by tampering @partial-block
Overview
Description
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.
Details
INFO
Published Date :
March 27, 2026, 9:17 p.m.
Last Modified :
July 15, 2026, 2:20 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c |
Solution
Update Handlebars to version 4.7.9 or later.
- Update Handlebars to version 4.7.9 or later.
- Use the runtime-only build.
- Audit registered helpers.
- Avoid untrusted third-party helpers.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33938.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33938 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33938
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33938 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33938 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jul. 15, 2026
Action Type Old Value New Value Changed Affected [{'cpes': ['cpe:/a:redhat:cluster_observability_operator:1.5::el9'], 'vendor': 'Red Hat', 'product': 'Cluster Observability Operator 1.5.0', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:openshift_devspaces:3.27::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Dev Spaces 3.27', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cryostat:4'], 'vendor': 'Red Hat', 'product': 'Cryostat 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}] [{'cpes': ['cpe:/a:redhat:cluster_observability_operator:1.5::el9'], 'vendor': 'Red Hat', 'product': 'Cluster Observability Operator 1.5.0', 'versions': [{'status': 'unaffected', 'version': '1782839279', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'cluster-observability-operator/logging-console-plugin-pf4-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cluster_observability_operator:1.5::el9'], 'vendor': 'Red Hat', 'product': 'Cluster Observability Operator 1.5.0', 'versions': [{'status': 'unaffected', 'version': '1782840539', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'cluster-observability-operator/logging-console-plugin-pf5-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cluster_observability_operator:1.5::el9'], 'vendor': 'Red Hat', 'product': 'Cluster Observability Operator 1.5.0', 'versions': [{'status': 'unaffected', 'version': '1782839996', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'cluster-observability-operator/troubleshooting-panel-console-plugin-pf6-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:openshift_devspaces:3.27::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Dev Spaces 3.27', 'versions': [{'status': 'unaffected', 'version': '1776744110', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'devspaces/code-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cryostat:4'], 'vendor': 'Red Hat', 'product': 'Cryostat 4', 'packageName': 'handlebars', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/elasticsearch6-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/elasticsearch-operator-bundle', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/elasticsearch-proxy-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/elasticsearch-rhel9-operator', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/kibana6-rhel8', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'packageName': 'openshift-logging/logging-curator5-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'packageName': 'handlebars', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'firefox', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'thunderbird', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'packageName': 'firefox', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': '389-ds:1.4/389-ds-base', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'firefox', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'grafana', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'mozjs60', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'thunderbird', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'packageName': 'firefox', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'packageName': 'thunderbird', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'packageName': 'rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'packageName': 'handlebars', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jul. 02, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:34342 Changed Affected [{'cpes': ['cpe:/a:redhat:openshift_devspaces:3.27::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Dev Spaces 3.27', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cryostat:4'], 'vendor': 'Red Hat', 'product': 'Cryostat 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}] [{'cpes': ['cpe:/a:redhat:cluster_observability_operator:1.5::el9'], 'vendor': 'Red Hat', 'product': 'Cluster Observability Operator 1.5.0', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:openshift_devspaces:3.27::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Dev Spaces 3.27', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cryostat:4'], 'vendor': 'Red Hat', 'product': 'Cryostat 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}] -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:openshift_devspaces:3.27::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Dev Spaces 3.27', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:logging:5'], 'vendor': 'Red Hat', 'product': 'Logging Subsystem for Red Hat OpenShift', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:cryostat:4'], 'vendor': 'Red Hat', 'product': 'Cryostat 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:openshift_ai'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift AI (RHOAI)', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}] Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-917 Added Reference https://access.redhat.com/errata/RHSA-2026:10175 Added Reference https://access.redhat.com/security/cve/CVE-2026-33938 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2452525 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33938.json -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-33938', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-03-31T00:00:00+00:00'} -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'handlebars-lang', 'product': 'handlebars.js', 'versions': [{'status': 'affected', 'version': '>= 4.0.0, < 4.7.9'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 31, 2026
Action Type Old Value New Value Added Reference https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r -
Initial Analysis by [email protected]
Mar. 31, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:* versions from (including) 4.0.0 up to (excluding) 4.7.9 Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r Types: Exploit, Vendor Advisory -
New CVE Received by [email protected]
Mar. 27, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-94 Added CWE CWE-843 Added Reference https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2 Added Reference https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9 Added Reference https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.