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
Trending — 3 sources updated this weekElevated
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%CVSS: 9.8Exploit: Elevated riskExposed: 0

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
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

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%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
54%
KEV
Not listed

Published

March 20, 2026

Last Modified

August 17, 2026

Advisory Details (8)

Auto-updated Aug 17, 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(4)

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 / EcosystemFixed in / 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 rangeFixed inDependents
node-flatted2.0.2~dfsg-1 ... 3.4.2~ds-1 (14 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
node-flatted3.2.7~ds-1, 3.2.7~ds-1+deb12u1, 3.4.1~ds-1, 3.4.2~ds-1——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-flatted3.2.7~ds-13.2.7~ds-1+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-flatted3.2.7~ds-1, 3.4.1~ds-13.4.2~ds-1—
npm(1)
PackageVulnerable rangeFixed inDependents
flatted—3.4.2—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 86× 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 122 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

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 in the National Vulnerability Database on March 20, 2026, with the most recent update on August 17, 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% probability of exploitation in the next 30 days, which ranks it in the top 45.9% of all 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?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33228, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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