CVE-2026-33228

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.8%, top 46% 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, nvd
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 9.8Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with the key "__proto__" returns Array.prototype via the inherited getter. This object is then treated as a legitimate parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype to the consumer. Any code that subsequently writes to that property will pollute the global prototype. This issue has been patched in version 3.4.2.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
75
EG Risk 75/100

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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
EPSS PROB
1.0%
EPSS %ILE
61st
KEV
Not listed

Published

March 20, 2026

Last Modified

September 7, 2026

Advisory Details (8)

Auto-updated Oct 5, 2026
Patch available. Sources: github, github_commit.
github_commit

commit 885ddcc33cf9 (WebReflection/flatted)

Fix landed in WebReflection/flatted commit 885ddcc33cf9 — awaiting tagged release

https://github.com/WebReflection/flatted/commit/885ddcc33cf9657caf38c57c7be45ae1c5272802
github Patch Available

Prototype Pollution via parse() in NodeJS flatted (CWE-1321) · Advisory · WebReflection/flatted · GitHub

https://github.com/WebReflection/flatted/security/advisories/GHSA-rf6f-7fwh-wjgh
redhat Patch Available

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33228.json
redhat Patch Available

2449872 – (CVE-2026-33228) CVE-2026-33228 flatted: Flatted: Prototype pollution vulnerability allows arbitrary code execution via crafted JSON.

https://bugzilla.redhat.com/show_bug.cgi?id=2449872
redhat Patch Available

CVE-2026-33228 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-33228
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:9742
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:34342
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:13826

Vendor Advisories for CVE-2026-33228(5)

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatcluster-observability-operator/troubleshooting-panel-console-plugin-pf6-rhel9:17828399962026-07-01redhat
redhatrhdh/rhdh-hub-rhel9:17779032622026-05-05redhat
redhatrhdh/rhdh-hub-rhel9:17767842862026-04-22redhat

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-flatted2.0.2~dfsg-1 ... 3.4.2~ds-1 (14 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
node-flatted3.2.7~ds-1, 3.2.7~ds-1+deb12u1, 3.4.1~ds-1, 3.4.2~ds-1, 3.4.4~ds-1
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
node-flatted3.2.7~ds-1
  • every version up to 3.2.7~ds-1+deb13u1: fixed in 3.2.7~ds-1+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
node-flatted3.2.7~ds-1, 3.4.1~ds-1
  • every version up to 3.4.2~ds-1: fixed in 3.4.2~ds-1
—
npm(1)
PackageVulnerable rangeFix by version rangeDependents
flatted—
  • every version up to 3.4.2: fixed in 3.4.2
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 27× 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 169 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. 2026-09-27 04:45 UTCOSV refresh
  9. 2026-09-26 15:58 UTCEPSS rescore
  10. 2026-09-26 00:26 UTCEPSS rescore
  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 14:52 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. 2026-09-07 14:01 UTCEG score recompute
  25. 2026-09-07 14:01 UTCVendor advisory
Show 75 more
  1. 2026-09-06 13:47 UTCEPSS rescore
  2. 2026-09-06 13:47 UTCEPSS rescore
  3. 2026-09-04 13:30 UTCVendor advisory
  4. 2026-09-04 12:25 UTCEG score recompute
  5. 2026-09-04 12:25 UTCVendor advisory
  6. 2026-09-04 05:06 UTCEPSS rescore
  7. 2026-09-02 14:11 UTCEPSS rescore
  8. 2026-09-01 13:53 UTCEPSS rescore
  9. 2026-09-01 04:39 UTCEPSS rescore
  10. 2026-09-01 04:39 UTCEPSS rescore
  11. 2026-08-31 13:37 UTCVendor advisory
  12. 2026-08-31 12:31 UTCEG score recompute
  13. 2026-08-31 12:31 UTCVendor advisory
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 01:22 UTCEPSS rescore
  16. 2026-08-28 21:41 UTCEPSS rescore
  17. 2026-08-27 14:25 UTCEPSS rescore
  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. 2026-08-17 12:13 UTCEG score recompute
  29. 2026-08-17 12:13 UTCVendor advisory
  30. 2026-08-16 14:56 UTCEPSS rescore
  31. 2026-08-16 10:59 UTCEG score recompute
  32. 2026-08-16 10:59 UTCVendor advisory
  33. 2026-08-16 02:14 UTCEPSS rescore
  34. 2026-08-15 01:30 UTCEPSS rescore
  35. 2026-08-14 23:31 UTCVendor advisory
  36. 2026-08-14 19:48 UTCVendor advisory
  37. 2026-08-14 14:35 UTCVendor advisory
  38. 2026-08-14 10:52 UTCVendor advisory
  39. 2026-08-14 07:09 UTCEG score recompute
  40. 2026-08-14 07:09 UTCVendor advisory
  41. 2026-08-13 22:00 UTCEPSS rescore
  42. 2026-08-13 01:33 UTCVendor advisory
  43. 2026-08-12 21:50 UTCEG score recompute
  44. 2026-08-12 21:50 UTCVendor advisory
  45. 2026-08-12 13:50 UTCEPSS rescore
  46. 2026-08-12 01:11 UTCVendor advisory
  47. 2026-08-11 21:22 UTCEG score recompute
  48. 2026-08-11 21:22 UTCVendor advisory
  49. 2026-08-11 08:31 UTCVendor advisory
  50. 2026-08-11 04:23 UTCEG score recompute
  51. 2026-08-11 04:23 UTCVendor advisory
  52. 2026-08-11 00:00 UTCEPSS rescore
  53. 2026-08-10 12:13 UTCVendor advisory
  54. 2026-08-10 07:55 UTCVendor advisory
  55. 2026-08-10 04:12 UTCVendor advisory
  56. 2026-08-10 00:29 UTCVendor advisory
  57. 2026-08-09 20:46 UTCVendor advisory
  58. 2026-08-09 17:03 UTCEG score recompute
  59. 2026-08-09 17:03 UTCVendor advisory
  60. 2026-08-09 13:46 UTCEPSS rescore
  61. 2026-08-09 13:19 UTCVendor advisory
  62. 2026-08-09 06:43 UTCEG score recompute
  63. 2026-08-09 06:43 UTCVendor advisory
  64. 2026-08-08 16:37 UTCEPSS rescore
  65. 2026-08-08 11:47 UTCVendor advisory
  66. 2026-08-08 08:04 UTCVendor advisory
  67. 2026-08-08 04:21 UTCVendor advisory
  68. 2026-08-08 00:38 UTCVendor advisory
  69. 2026-08-07 20:55 UTCVendor advisory
  70. 2026-08-07 17:12 UTCEG score recompute
  71. 2026-08-07 17:12 UTCVendor advisory
  72. 2026-08-06 19:16 UTCEG score recompute
  73. 2026-08-06 19:16 UTCVendor advisory
  74. 2026-08-06 13:46 UTCEPSS rescore
  75. 2026-08-06 08:53 UTCVendor advisory

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

Same product

1 shown

Debian:11:node-flatted

Frequently asked(5)

What is CVE-2026-33228?
CVE-2026-33228 is a critical vulnerability published on March 20, 2026. flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with…
When was CVE-2026-33228 disclosed?
CVE-2026-33228 was first published on March 20, 2026, with the most recent update on September 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33228 actively exploited?
CVE-2026-33228 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (61st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33228?
CVE-2026-33228 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-33228?
A fix for CVE-2026-33228 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33228 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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