CVE-2026-107577

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

GHSA-q3hj-9493-685w ↗EUVD-2026-94858 ↗

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.
Progressive Robot Ltd hMailServer >= 6.0.0, < 6.3.6
fixed in 6.3.6
CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
ETK-2026-1285Zero's internal tracking ID, independent of the CVE number., permanent identifier
9d 02h 28msince last run
41mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = cve.org publication
trigger signal (cve.org) +0hwaiting for further signals+87h31m
0
+2h
+4h
+6h
+8h
+10h

description

hMailServer 6.0.0 through 6.3.5 can mishandle certain MIME message headers, causing excessive processing or a worker thread to remain stuck. A remote unauthenticated attacker who can submit messages to the server may disrupt SMTP, IMAP, POP3, delivery, or REST service availability; the non-terminating condition depends on affected attachment-blocker processing.

mitigation

Upgrade hMailServer to version 6.3.6. Until the upgrade is complete, restrict untrusted message submission where possible and monitor mail-service worker exhaustion or sustained high CPU use.

fixed in 6.3.6

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.
0.43%35th percentile
agent run time
41m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-08 11:46Z
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

Contextual: an exploit technique exists, but no deterministic check could cover this one.

source signals

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

  1. 2026-10-08 11:46Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-107577

{
  "etk_id": "ETK-2026-1285",
  "cve_id": "CVE-2026-107577",
  "display_id": "CVE-2026-107577",
  "ghsa_id": "GHSA-q3hj-9493-685w",
  "euvd_id": "EUVD-2026-94858",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Infinite loop and complexity flaws in hMailServer MIME processing",
  "summary": "hMailServer 6.0.0 through 6.3.5 can mishandle certain MIME message headers, causing excessive processing or a worker thread to remain stuck. A remote unauthenticated attacker who can submit messages to the server may disrupt SMTP, IMAP, POP3, delivery, or REST service availability; the non-terminating condition depends on affected attachment-blocker processing.",
  "mitigation": "Upgrade hMailServer to version 6.3.6. Until the upgrade is complete, restrict untrusted message submission where possible and monitor mail-service worker exhaustion or sustained high CPU use.",
  "vendor": "Progressive Robot Ltd",
  "product": "hMailServer",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 6.0.0, < 6.3.6"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "6.3.6"
      ],
      "package_name": "hMailServer",
      "purl": null
    }
  ],
  "cwes": [
    835
  ],
  "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": 0.357,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 41.37698436666667,
  "t0_at": "2026-10-08T11:46:51.086000+00:00",
  "signals": {
    "trigger_signal": {
      "at": "2026-10-08T11:46:51.086000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-08T11:46:51.086000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-107577"
    }
  }
}

published 2026-10-12 02:36Z
last change 2026-10-21 05:31Z

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