CVE-2026-128338

waiting for further signalsZero needs more public information before it can validate it.

GHSA-6p4m-pmw8-v6w9 ↗EUVD-2026-125039 ↗

no check availablenot proven exploitable
cve.orgpublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).−28dkevAttacks confirmed in the real world.
exceljs <= 5.0.2
fixed in 5.1.0
CWE-770 Allocation of Resources Without Limits or Throttling
ETK-2026-4370Zero's internal tracking ID, independent of the CVE number., permanent identifier
pkg:npm/exceljs-hardened
19h 41msince last run
16mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = cve.org publication
public poc−28dtrigger signal (cve.org) +0dwaiting for further signals+0.0d
−20d
−10d

description

ExcelJS through 4.4.0 is affected by memory exhaustion when parsing workbooks with an unbounded worksheet column maximum. An attacker who can provide a workbook for processing can cause xlsx.load() to exhaust heap memory and terminate the application.

mitigation

Upgrade exceljs-hardened to 5.1.0 or later.

fixed in 5.1.0

check
no
exploit
no
automationDeterministic: a check that runs on its own, the same request on every target. Contextual: an agentic technique that needs to be applied per target, for bugs that depend on contextual flows.
contextual
auth requiredWhether an attacker needs an account first, based on the CVSS vector's Privileges Required.
no
EPSSEstimate of the chance this CVE is exploited in the next 30 days. Refreshed daily.
–
agent run time
16m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-11-13 09:33Z
Δ to public pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).
−28d
Δ to kevAttacks confirmed in the real world.
–

outcome

Contextual, not validated: no deterministic check could cover this one, and no technique passed our review.

source signals

Public signals that triggered or updated the pipeline. These are inputs for the deltas above.

  1. 2026-10-16 16:01Z
  2. 2026-11-13 09:33Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-128338

{
  "etk_id": "ETK-2026-4370",
  "cve_id": "CVE-2026-128338",
  "display_id": "CVE-2026-128338",
  "ghsa_id": "GHSA-6p4m-pmw8-v6w9",
  "euvd_id": "EUVD-2026-125039",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Memory exhaustion in ExcelJS worksheet parsing",
  "summary": "ExcelJS through 4.4.0 is affected by memory exhaustion when parsing workbooks with an unbounded worksheet column maximum. An attacker who can provide a workbook for processing can cause xlsx.load() to exhaust heap memory and terminate the application.",
  "mitigation": "Upgrade exceljs-hardened to 5.1.0 or later.",
  "vendor": "exceljs",
  "product": "exceljs",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "<= 5.0.2"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        "5.1.0"
      ],
      "package_name": "exceljs-hardened",
      "purl": "pkg:npm/exceljs-hardened"
    }
  ],
  "cwes": [
    770
  ],
  "cvss_score": 8.7,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 16.359571633333335,
  "t0_at": "2026-11-13T09:33:37.051000+00:00",
  "signals": {
    "public_poc": {
      "at": "2026-10-16T16:01:10+00:00",
      "days": -27.730868645833333,
      "is_lower_bound": false,
      "measured_at": "2026-11-13T09:33:37.051000+00:00",
      "url": "https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-w57r-3mm6-w6g7"
    },
    "trigger_signal": {
      "at": "2026-11-13T09:33:37.051000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-11-13T09:33:37.051000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-128338"
    }
  }
}

published 2026-11-13 09:44Z
last change 2026-11-14 05:26Z

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