CVE-2026-107300

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

GHSA-5x5g-h9x8-2fh9 ↗EUVD-2026-95111 ↗

no check availablenot proven exploitable
cve.orgpublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).kevAttacks confirmed in the real world.
mcollina msgpack5 < 6.1.0
fixed in >= 6.1.0
CWE-674 Uncontrolled Recursion
ETK-2026-1041Zero's internal tracking ID, independent of the CVE number., permanent identifier
pkg:npm/msgpack5
12d 18h 45msince last run
24mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = trigger signal
trigger signal (cve.org) +0hwaiting for further signals+11h41m
0
+2h
+4h
+6h
+8h
+10h

description

msgpack5 versions before 6.1.0 have a denial-of-service flaw in the streaming decoder. A remote peer able to send a chunk with many valid MessagePack values can exhaust the JavaScript call stack and interrupt the process or stream.

mitigation

Upgrade msgpack5 to version 6.1.0 or later. Until upgraded, limit the number of MessagePack values accepted per chunk or split large batches before decoding.

fixed in >= 6.1.0

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.
–
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.
0.43%35th percentile
agent run time
24m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-08 17:11Z
Δ to public pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).
–
Δ to kevAttacks confirmed in the real world.
–

outcome

No artifact: an exploit or check was attempted but could not be produced at this moment.

source signals

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

  1. 2026-10-08 17:11Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-107300

{
  "etk_id": "ETK-2026-1041",
  "cve_id": "CVE-2026-107300",
  "display_id": "CVE-2026-107300",
  "ghsa_id": "GHSA-5x5g-h9x8-2fh9",
  "euvd_id": "EUVD-2026-95111",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Stack exhaustion in msgpack5 streaming decoder",
  "summary": "msgpack5 versions before 6.1.0 have a denial-of-service flaw in the streaming decoder. A remote peer able to send a chunk with many valid MessagePack values can exhaust the JavaScript call stack and interrupt the process or stream.",
  "mitigation": "Upgrade msgpack5 to version 6.1.0 or later. Until upgraded, limit the number of MessagePack values accepted per chunk or split large batches before decoding.",
  "vendor": "mcollina",
  "product": "msgpack5",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "< 6.1.0"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        ">= 6.1.0"
      ],
      "package_name": "msgpack5",
      "purl": "pkg:npm/msgpack5"
    }
  ],
  "cwes": [
    674
  ],
  "cvss_score": 7.5,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss_score": 0.0043,
  "epss_percentile": 0.3578,
  "epss_asof": "2026-10-21",
  "automation": "deterministic",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 23.9926661,
  "t0_at": "2026-10-08T17:11:13.552000+00:00",
  "signals": {
    "trigger_signal": {
      "at": "2026-10-08T17:11:13.552000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-08T17:11:13.552000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-107300"
    }
  }
}

published 2026-10-09 04:28Z
last change 2026-10-21 22:34Z

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