CVE-2026-71889

validatedZero produced an exploit or a check.

GHSA-hqqj-v58h-gr7x ↗EUVD-2026-91990 ↗

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).kevAttacks confirmed in the real world.
Legion of the Bouncy Castle Inc. BC-JAVA < 1.86; >= 2.73.0, < 2.73.13; >= 1.0.4, < 1.0.13; >= 2.0.0, < 2.0.13; >= 2.1.0, < 2.1.13
fixed in 1.86, 2.73.13, 1.0.13, 2.0.13, 2.1.13
CWE-295 Improper Certificate Validation
ETK-2026-439, permanent identifier
+3h03mTTV
18mAI analysisAnalysis: how long the AI spent reversing this signal.
Check if you are vulnerable
timeline
0 = cve.org publication
trigger signal (cve.org) +0hcheck available+3h03magent stopped
0
+1h
+2h

description

Affected BC-JAVA certificate-path reviewer implementations can approve a chain whose end-entity certificate falls outside an issuing CA's name constraints. An attacker could have an improperly scoped certificate accepted when an application relies on this reviewer to make its trust decision.

mitigation

Upgrade bcpkix and bcprov to 1.86 or later, bcpkix-lts8on to 2.73.13 or later, and bcpkix-fips to 1.0.13, 2.0.13, or 2.1.13 or later for the applicable release line. Until upgraded, do not use PKIXCertPathReviewer as the trust-decision mechanism; use the PKIX certificate validator instead.

fixed in 1.86, 2.73.13, 1.0.13, 2.0.13, 2.1.13

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.
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.
0.17%5th percentile
agent run time
18m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-03 08:31Z
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

Mechanism verified: the exploit fired on the vulnerable build and stayed silent on the patched one, but the server it ran against was ours, so no check ships for it.

source signals

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

  1. 2026-10-03 08:31Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-71889

{
  "etk_id": "ETK-2026-439",
  "cve_id": "CVE-2026-71889",
  "display_id": "CVE-2026-71889",
  "ghsa_id": "GHSA-hqqj-v58h-gr7x",
  "euvd_id": "EUVD-2026-91990",
  "status": "published",
  "anchor_state": "anchored",
  "title": "PKIXCertPathReviewer name-constraint validation flaw",
  "summary": "Affected BC-JAVA certificate-path reviewer implementations can approve a chain whose end-entity certificate falls outside an issuing CA's name constraints. An attacker could have an improperly scoped certificate accepted when an application relies on this reviewer to make its trust decision.",
  "mitigation": "Upgrade bcpkix and bcprov to 1.86 or later, bcpkix-lts8on to 2.73.13 or later, and bcpkix-fips to 1.0.13, 2.0.13, or 2.1.13 or later for the applicable release line. Until upgraded, do not use PKIXCertPathReviewer as the trust-decision mechanism; use the PKIX certificate validator instead.",
  "vendor": "Legion of the Bouncy Castle Inc.",
  "product": "BC-JAVA",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < 1.86"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "1.86"
      ],
      "package_name": "bcpkix",
      "purl": null
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < 1.86"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "1.86"
      ],
      "package_name": "bcprov",
      "purl": null
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 2.73.0, < 2.73.13"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "2.73.13"
      ],
      "package_name": "bcpkix-lts8on",
      "purl": null
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 1.0.4, < 1.0.13",
        ">= 2.0.0, < 2.0.13",
        ">= 2.1.0, < 2.1.13"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "1.0.13",
        "2.0.13",
        "2.1.13"
      ],
      "package_name": "bcpkix-fips",
      "purl": null
    }
  ],
  "cwes": [
    295
  ],
  "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:H/VA:N/SC:N/SI:N/SA:N/U:Amber",
  "epss_score": 0.0017,
  "epss_percentile": 0.0557,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": true,
  "check_confidence_basis": "mechanism_verified",
  "exploit": false,
  "pipeline_minutes": 18.271798,
  "t0_at": "2026-10-03T08:31:01.178000+00:00",
  "signals": {
    "check": {
      "at": "2026-10-03T11:34:12.415064+00:00",
      "days": 0.12721339194444445,
      "is_lower_bound": false,
      "measured_at": "2026-10-03T08:31:01.178000+00:00",
      "url": null
    },
    "trigger_signal": {
      "at": "2026-10-03T08:31:01.178000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-03T08:31:01.178000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-71889"
    }
  }
}

published 2026-10-03 09:12Z
last change 2026-10-21 17:13Z

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