ETK-2026-2558Zero's internal tracking ID, independent of the CVE number.

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

GHSA-26q8-h657-pf84 ↗

no check availablenot proven exploitable
awaiting cvepublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).kevAttacks confirmed in the real world.
npm:bun < 1.4.4
fixed in 1.4.4
CWE-295 Improper Certificate Validation
ETK-2026-2558Zero's internal tracking ID, independent of the CVE number., no cve assigned
pkg:npm/bun
cvss7.0ethiack provisional
3h 30msince last run
17mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = trigger signal
trigger signal +0dwaiting for further signals+1.7d
0
+1d
+2d

description

Bun 1.4.3 and earlier can trust TLS certificate chains associated with compromised emSign certificate authority keys. An attacker able to intercept a Bun TLS connection could impersonate a server and read or alter traffic, including downloaded packages; compiled Bun executables remain affected until rebuilt. Connections using Bun's default trust store are exposed.

mitigation

Upgrade Bun to 1.4.4 and rebuild executables produced with bun build --compile. Until upgraded, configure an explicit per-connection or installation CA bundle that excludes the affected emSign roots.

fixed in 1.4.4

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.
–
EPSSEstimate of the chance this CVE is exploited in the next 30 days. Refreshed daily.
–
agent run time
17m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
not published yet
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. 2026-10-23 02:02Z

this entry in the feed

GET /api/v1/feed/ETK-2026-2558

{
  "etk_id": "ETK-2026-2558",
  "cve_id": null,
  "display_id": "ETK-2026-2558",
  "ghsa_id": "GHSA-26q8-h657-pf84",
  "euvd_id": null,
  "status": "published",
  "anchor_state": "awaiting_cve",
  "title": "Compromised CA trust in Bun TLS certificate store",
  "summary": "Bun 1.4.3 and earlier can trust TLS certificate chains associated with compromised emSign certificate authority keys. An attacker able to intercept a Bun TLS connection could impersonate a server and read or alter traffic, including downloaded packages; compiled Bun executables remain affected until rebuilt. Connections using Bun's default trust store are exposed.",
  "mitigation": "Upgrade Bun to 1.4.4 and rebuild executables produced with `bun build --compile`. Until upgraded, configure an explicit per-connection or installation CA bundle that excludes the affected emSign roots.",
  "vendor": "npm",
  "product": "npm:bun",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "< 1.4.4"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        "1.4.4"
      ],
      "package_name": "bun",
      "purl": "pkg:npm/bun"
    }
  ],
  "cwes": [
    295
  ],
  "cvss_score": 7,
  "cvss_src": "ethiack_provisional",
  "cvss_vector": null,
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "deterministic",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 17.023813733333334,
  "t0_at": null,
  "signals": {
    "trigger_signal": {
      "at": "2026-10-23T02:02:06+00:00",
      "days": -1.8381025353356482,
      "is_lower_bound": true,
      "measured_at": "2026-10-24T22:08:58.083408+00:00",
      "url": "https://github.com/oven-sh/bun/security/advisories/GHSA-26q8-h657-pf84"
    }
  }
}

published 2026-10-24 18:33Z
last change 2026-10-24 21:56Z

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