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Vulnerabilities/CVE-2026-76838Public Intelligence Dossier
Source: Source type: NVD · Limited verification•Last verified: •Collection Degraded
CVE-2026-76838Unknown / EvaluatingHIGH (raw)CVSS 8.5CWE-918

Hi.Events validates a webhook destination only when it is registered, never when it is used

Published: 24 Aug 2026•Last updated: 12 Oct 2026, 08:40 PM IST•Source identifier: disclosure@vulncheck.com
Dossier completeness: source-provided sections 1 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
8.5HIGH (raw)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Metric sourcedisclosure@vulncheck.com
EPSS probability
0.4%0.004
Percentile35th
Weakness type
CWE-918
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

Hi.Events validates a webhook destination only when it is registered, never when it is used. NoInternalUrlRule in backend/app/Validators/Rules/NoInternalUrlRule.php resolves the hostname with gethostbyname() and rejects private and reserved ranges, which any public hostname passes. At dispatch, WebhookDispatchService takes the stored URL and calls it through spatie/laravel-webhook-server without repeating the check, and backend/config/webhook-server.php sets no Guzzle options, so redirect following remains enabled by default. A destination that answers with a redirect to a loopback, private or cloud metadata address therefore causes the server to issue that request, and changing the hostname's DNS record after registration reaches the same result because no resolution is repeated. The response is not discarded: WebhookResponseHandlerService stores the body on the webhook log and WebhookLogResource returns it from the webhook logs endpoint, so the requester reads what the internal service replied rather than inferring it. Both event and organizer webhooks share the rule and the dispatch path. Version 1.11.1-beta revalidates at dispatch, pins the validated address, checks every redirect hop, and decodes IPv6 transition addresses that previously bypassed the filter.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

0 source-backed products
Affected products and versions (source)Not provided by source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched ssrf (CWE-918)

Exposure

  1. Identify affected server-side request features and deployed versions.Telemetry: Application inventory · The specific feature must be confirmed from the advisory. · Rule ssrf

Exploitation evidence

  1. Review unusual outbound connections from the affected service to internal or metadata endpoints.Telemetry: DeviceNetworkEvents · Outbound patterns can support SSRF hunting. · Rule ssrf

Response

  1. Verify the vendor fix and confirm expected egress after deployment.Telemetry: DeviceNetworkEvents · Post-change telemetry helps validate mitigation. · Rule ssrf

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
disclosure@vulncheck.com
Record status · verification
UPDATED · NVD API
CPE
Unknown
Detection Hunting Query

— No published hunting query names this record. Browse community and library queries instead.

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.