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Vulnerability details: VCID-ts65-xn5b-xkam
Vulnerability ID VCID-ts65-xn5b-xkam
Aliases CVE-2026-33937
GHSA-2w6w-674q-4c4q
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 9.0
Risk 4.5
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-94 Improper Control of Generation of Code ('Code Injection')
CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 9.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33937.json
epss 0.0024 https://api.first.org/data/v1/epss?cve=CVE-2026-33937
epss 0.0024 https://api.first.org/data/v1/epss?cve=CVE-2026-33937
epss 0.0024 https://api.first.org/data/v1/epss?cve=CVE-2026-33937
epss 0.0024 https://api.first.org/data/v1/epss?cve=CVE-2026-33937
cvssv3.1_qr CRITICAL https://github.com/advisories/GHSA-2w6w-674q-4c4q
cvssv3.1 9.8 https://github.com/handlebars-lang/handlebars.js
generic_textual CRITICAL https://github.com/handlebars-lang/handlebars.js
cvssv3.1 9.8 https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
generic_textual CRITICAL https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
ssvc Track* https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
cvssv3.1 9.8 https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
generic_textual CRITICAL https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
ssvc Track* https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
cvssv3.1 9.8 https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
cvssv3.1_qr CRITICAL https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
generic_textual CRITICAL https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
ssvc Track* https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
cvssv3.1 9.8 https://nvd.nist.gov/vuln/detail/CVE-2026-33937
generic_textual CRITICAL https://nvd.nist.gov/vuln/detail/CVE-2026-33937
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33937.json
https://api.first.org/data/v1/epss?cve=CVE-2026-33937
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-33937
https://github.com/handlebars-lang/handlebars.js
https://nvd.nist.gov/vuln/detail/CVE-2026-33937
1132141 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1132141
2452523 https://bugzilla.redhat.com/show_bug.cgi?id=2452523
68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2 https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
GHSA-2w6w-674q-4c4q https://github.com/advisories/GHSA-2w6w-674q-4c4q
GHSA-2w6w-674q-4c4q https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
RHSA-2026:10175 https://access.redhat.com/errata/RHSA-2026:10175
v4.7.9 https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33937.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/handlebars-lang/handlebars.js
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:Y/T:T/P:M/B:A/M:M/D:R/2026-03-31T14:23:06Z/ Found at https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:Y/T:T/P:M/B:A/M:M/D:R/2026-03-31T14:23:06Z/ Found at https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:Y/T:T/P:M/B:A/M:M/D:R/2026-03-31T14:23:06Z/ Found at https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2026-33937
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.47541
EPSS Score 0.0024
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:49:40.967762+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/33xxx/CVE-2026-33937.json 38.6.0