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CVE-2026-55376

CVE-2026-55376

validatedZero produced an exploit or a check.

GHSA-wcgw-9hfw-f6f2 ↗EUVD-2026-98740 ↗

check availableZero validated a working check for it.not proven exploitableZero has a detection check, but hasn't produced a full working exploit yet.
cve.orgpublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).−123dkevAttacks confirmed in the real world.
heymrun heym <= ddc8941 (<= 0.0.39)
fixed in 0.0.40
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
ETK-2026-1490Zero's internal tracking ID, independent of the CVE number., permanent identifier
cvss8.8cna vendorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
+3h48mTTV
46mAI analysisAnalysis: how long the AI spent reversing this signal.
Check if you are vulnerable
timeline
0 = trigger signal
public poc−4.1motrigger signal (cve.org) +0mocheck available+0.0moagent stopped
−3mo
−2mo
−1mo

description

Heym versions before 0.0.40 do not adequately restrict Agent custom Python tools. An authenticated user able to create or edit a relevant workflow may gain command execution and file access as the backend application user. Merely invoking workflows through the portal is not sufficient without control over the custom tool.

mitigation

Upgrade heym to version 0.0.40 or later. Until upgraded, restrict who can create or modify workflows with Agent custom Python tools.

fixed in 0.0.40

check
available
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.
deterministic
auth requiredWhether an attacker needs an account first, based on the CVSS vector's Privileges Required.
yes, low privileges
EPSSEstimate of the chance this CVE is exploited in the next 30 days. Refreshed daily.
0.36%28th percentile
agent run time
46m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-13 15:12Z
Δ to public pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).
−123d
Δ to kevAttacks confirmed in the real world.
–

outcome

Check only, differential: the check fires on the vulnerable build and is silent on the patched one.

source signals

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

  1. 2026-06-12 06:34Z
  2. 2026-10-13 15:12Z
    cve_org: trigger signal, started the run
    https://www.cve.org/CVERecord?id=CVE-2026-55376

this entry in the feed

GET /api/v1/feed/CVE-2026-55376

{
  "etk_id": "ETK-2026-1490",
  "cve_id": "CVE-2026-55376",
  "display_id": "CVE-2026-55376",
  "ghsa_id": "GHSA-wcgw-9hfw-f6f2",
  "euvd_id": "EUVD-2026-98740",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Python tool sandbox escape in heym",
  "summary": "Heym versions before 0.0.40 do not adequately restrict Agent custom Python tools. An authenticated user able to create or edit a relevant workflow may gain command execution and file access as the backend application user. Merely invoking workflows through the portal is not sufficient without control over the custom tool.",
  "mitigation": "Upgrade heym to version 0.0.40 or later. Until upgraded, restrict who can create or modify workflows with Agent custom Python tools.",
  "vendor": "heymrun",
  "product": "heym",
  "affected": [
    {
      "affected_notes": [
        "<= ddc8941 (<= 0.0.39)"
      ],
      "affected_ranges": [],
      "ecosystem": null,
      "fixed_versions": [
        "0.0.40"
      ],
      "package_name": "heymrun/heym",
      "purl": null
    }
  ],
  "cwes": [
    78
  ],
  "cvss_score": 8.8,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss_score": 0.0036,
  "epss_percentile": 0.2866,
  "epss_asof": "2026-10-21",
  "automation": "deterministic",
  "check": true,
  "check_confidence_basis": "differential",
  "exploit": false,
  "pipeline_minutes": 46.36783805,
  "t0_at": "2026-10-13T15:12:49.604000+00:00",
  "signals": {
    "check": {
      "at": "2026-10-13T19:00:56.168522+00:00",
      "days": 0.1584093115972222,
      "is_lower_bound": false,
      "measured_at": "2026-10-13T15:12:49.604000+00:00",
      "url": null
    },
    "public_poc": {
      "at": "2026-06-12T06:34:00+00:00",
      "days": -123.36029634259259,
      "is_lower_bound": false,
      "measured_at": "2026-10-13T15:12:49.604000+00:00",
      "url": "https://github.com/heymrun/heym/security/advisories/GHSA-wcgw-9hfw-f6f2"
    },
    "trigger_signal": {
      "at": "2026-10-13T15:12:49.604000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-13T15:12:49.604000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-55376"
    }
  }
}

published 2026-10-13 18:14Z
last change 2026-10-21 20:26Z

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