CVE-2026-33939

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 53% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. {{*n}}), the compiled template calls lookupProperty(decorators, "n"), which returns undefined. The runtime then immediately invokes the result as a function, causing an unhandled TypeError: ... is not a function that crashes the Node.js process. Any application that compiles user-supplied templates without wrapping the call in a try/catch is vulnerable to a single-request Denial of Service. Version 4.7.9 fixes the issue. Some workarounds are available. Wrap compilation and rendering in try/catch. Validate template input before passing it to compile(); reject templates containing decorator syntax ({{*...}}) if decorators are not used in your application. Use the pre-compilation workflow; compile templates at build time and serve only pre-compiled templates; do not call compile() at request time.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
EPSS PROB
0.8%
EPSS %ILE
53rd
KEV
Not listed

Published

March 27, 2026

Last Modified

September 4, 2026

Advisory Details (8)

Auto-updated Jul 7, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, redhat, github_commit.
redhat Patch Available

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33939.json
github Patch Available🟡 PoC Available

Denial of Service via Malformed Decorator Syntax in Template Compilation · Advisory · handlebars-lang/handlebars.js · GitHub

https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-9cx6-37pm-9jff
redhat Patch Available

2452508 – (CVE-2026-33939) CVE-2026-33939 handlebars.js: Handlebars.js: Denial of Service via malformed decorator syntax in template compilation

https://bugzilla.redhat.com/show_bug.cgi?id=2452508
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-33939
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:34342
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:10175
github_release Patch Available

v4.7.9

Patch available: handlebars-lang/handlebars.js v4.7.9

https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9
github_commit Patch Available

commit 68d8df5a88e0 (handlebars-lang/handlebars.js)

Patch available: handlebars-lang/handlebars.js v4.7.9 (contains commit 68d8df5a88e0)

https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2

Vendor Advisories for CVE-2026-33939(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatcluster-observability-operator/troubleshooting-panel-console-plugin-pf6-rhel9:17828399962026-07-01redhat
redhatdevspaces/code-rhel9:17767441102026-04-23redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
node-handlebars3:4.7.6+~4.1.0-2 ... 3:4.7.9-5 (8 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
node-handlebars3:4.7.7+~4.1.0-1 ... 3:4.7.9-6 (7 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
node-handlebars3:4.7.7+~4.1.0-1 ... 3:4.7.9-6 (7 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
node-handlebars3:4.7.7+~4.1.0-1
  • every version up to 3:4.7.9-1: fixed in 3:4.7.9-1
—
npm(1)
PackageVulnerable rangeFix by version rangeDependents
handlebars—
  • 4.0.0 up to 4.7.9: fixed in 4.7.9
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 135 total refreshes for this CVE.

  1. 2026-10-05 17:42 UTCEPSS rescore
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 14:25 UTCEPSS rescore
  4. 2026-10-01 19:49 UTCEPSS rescore
  5. 2026-09-30 15:03 UTCEPSS rescore
  6. 2026-09-28 13:51 UTCEPSS rescore
  7. 2026-09-27 13:48 UTCEPSS rescore
  8. 2026-09-26 15:58 UTCEPSS rescore
  9. 2026-09-26 00:26 UTCEPSS rescore
  10. 2026-09-23 19:04 UTCOSV refresh
  11. 2026-09-20 20:15 UTCEPSS rescore
  12. 2026-09-18 19:28 UTCEPSS rescore
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-17 19:30 UTCEPSS rescore
  15. 2026-09-16 14:08 UTCEPSS rescore
  16. 2026-09-16 05:15 UTCEPSS rescore
  17. 2026-09-15 03:11 UTCEPSS rescore
  18. 2026-09-13 16:47 UTCEPSS rescore
  19. 2026-09-12 15:01 UTCEPSS rescore
  20. 2026-09-11 14:53 UTCEPSS rescore
  21. 2026-09-11 09:37 UTCEPSS rescore
  22. 2026-09-10 09:34 UTCEPSS rescore
  23. 2026-09-08 22:00 UTCEPSS rescore
  24. 2026-09-07 16:01 UTCEPSS rescore
  25. 2026-09-06 13:47 UTCEPSS rescore
Show 75 more
  1. 2026-09-04 13:30 UTCEG score recompute
  2. 2026-09-04 13:30 UTCVendor advisory
  3. 2026-09-04 12:23 UTCEG score recompute
  4. 2026-09-04 12:23 UTCVendor advisory
  5. 2026-09-04 05:06 UTCEPSS rescore
  6. 2026-09-02 14:12 UTCEPSS rescore
  7. 2026-09-01 13:53 UTCEPSS rescore
  8. 2026-09-01 13:51 UTCEG score recompute
  9. 2026-09-01 13:51 UTCVendor advisory
  10. 2026-09-01 12:24 UTCEG score recompute
  11. 2026-09-01 12:24 UTCVendor advisory
  12. 2026-09-01 04:39 UTCEPSS rescore
  13. 2026-08-30 19:17 UTCEPSS rescore
  14. 2026-08-30 01:22 UTCEPSS rescore
  15. 2026-08-28 21:41 UTCEPSS rescore
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 13:49 UTCEPSS rescore
  19. 2026-08-24 14:17 UTCEPSS rescore
  20. 2026-08-23 00:19 UTCEPSS rescore
  21. 2026-08-21 23:49 UTCEPSS rescore
  22. 2026-08-20 22:55 UTCEPSS rescore
  23. 2026-08-20 22:55 UTCEPSS rescore
  24. 2026-08-19 17:03 UTCEPSS rescore
  25. 2026-08-18 13:48 UTCEPSS rescore
  26. 2026-08-17 13:47 UTCEPSS rescore
  27. 2026-08-16 14:56 UTCEPSS rescore
  28. 2026-08-16 09:56 UTCEG score recompute
  29. 2026-08-16 09:56 UTCVendor advisory
  30. 2026-08-16 02:14 UTCEPSS rescore
  31. 2026-08-15 01:30 UTCEPSS rescore
  32. 2026-08-14 19:25 UTCVendor advisory
  33. 2026-08-14 06:15 UTCEG score recompute
  34. 2026-08-14 06:15 UTCVendor advisory
  35. 2026-08-13 22:00 UTCEPSS rescore
  36. 2026-08-12 20:33 UTCEG score recompute
  37. 2026-08-12 20:33 UTCVendor advisory
  38. 2026-08-12 13:50 UTCEPSS rescore
  39. 2026-08-11 20:43 UTCEG score recompute
  40. 2026-08-11 20:43 UTCVendor advisory
  41. 2026-08-11 03:44 UTCEG score recompute
  42. 2026-08-11 03:44 UTCVendor advisory
  43. 2026-08-11 00:00 UTCEPSS rescore
  44. 2026-08-10 07:54 UTCVendor advisory
  45. 2026-08-09 18:51 UTCEG score recompute
  46. 2026-08-09 18:51 UTCVendor advisory
  47. 2026-08-09 13:46 UTCEPSS rescore
  48. 2026-08-09 05:48 UTCEG score recompute
  49. 2026-08-09 05:48 UTCVendor advisory
  50. 2026-08-08 16:37 UTCEPSS rescore
  51. 2026-08-08 05:18 UTCEG score recompute
  52. 2026-08-08 05:18 UTCVendor advisory
  53. 2026-08-07 16:15 UTCVendor advisory
  54. 2026-08-06 18:34 UTCEG score recompute
  55. 2026-08-06 18:34 UTCVendor advisory
  56. 2026-08-06 13:46 UTCEPSS rescore
  57. 2026-08-06 00:44 UTCEG score recompute
  58. 2026-08-06 00:44 UTCVendor advisory
  59. 2026-08-05 19:17 UTCEPSS rescore
  60. 2026-08-04 15:10 UTCEPSS rescore
  61. 2026-08-04 10:38 UTCEPSS rescore
  62. 2026-08-03 23:06 UTCEG score recompute
  63. 2026-08-03 23:06 UTCVendor advisory
  64. 2026-08-03 10:36 UTCEPSS rescore
  65. 2026-08-02 15:09 UTCEG score recompute
  66. 2026-08-02 15:09 UTCVendor advisory
  67. 2026-08-02 02:27 UTCEPSS rescore
  68. 2026-08-01 04:16 UTCEPSS rescore
  69. 2026-07-30 16:28 UTCEPSS rescore
  70. 2026-07-30 01:30 UTCEPSS rescore
  71. 2026-07-27 14:13 UTCEPSS rescore
  72. 2026-07-26 14:54 UTCEPSS rescore
  73. 2026-07-26 14:54 UTCEPSS rescore
  74. 2026-07-25 14:18 UTCEPSS rescore
  75. 2026-07-25 14:18 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-33939?
CVE-2026-33939 is a high vulnerability published on March 27, 2026. Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. {{n}}), the compiled template calls lookupProperty(decorators, "n"), which returns…
When was CVE-2026-33939 disclosed?
CVE-2026-33939 was first published on March 27, 2026, with the most recent update on September 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33939 actively exploited?
CVE-2026-33939 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33939?
CVE-2026-33939 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-33939?
A fix for CVE-2026-33939 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33939 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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