CVE-2026-33938

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7%, top 49% 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
8.1EG
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: 8.1Exploit: 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, 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.

CVSS v3
8.1
EG Score
8.1HIGHmedium confidence
EG Risk
52
EG Risk 52/100

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
Severity81% × 45%
Exploitation40% × 40%
Automatability0% × 15%
EPSS PROB
0.8%
EPSS %ILE
56th
KEV
Not listed

Published

March 27, 2026

Last Modified

September 4, 2026

Advisory Details (7)

Auto-updated Jun 30, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github, redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33938.json
github Patch Available🟡 PoC Available

JavaScript Injection via AST Type Confusion by tampering @partial-block · Advisory · handlebars-lang/handlebars.js · GitHub

https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r
redhat Patch Available

2452525 – (CVE-2026-33938) CVE-2026-33938 handlebars: Handlebars: Arbitrary code execution via @partial-block overwrite

https://bugzilla.redhat.com/show_bug.cgi?id=2452525
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-33938
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-2026-33938(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(3)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 24× 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 136 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-33938?
CVE-2026-33938 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, 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…
When was CVE-2026-33938 disclosed?
CVE-2026-33938 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-2026-33938 actively exploited?
CVE-2026-33938 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (56th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33938?
CVE-2026-33938 has a CVSS base score of 8.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-33938?
A fix for CVE-2026-33938 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33938 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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