CVE-2025-54320Network attack vector

Email bombing via unthrottled invite requests

Published Nov 18, 2025 · Updated Nov 19, 2025

Improper rate limiting in Ascertia SigningHub 8.6.8 and earlier allows remote authenticated users to flood a target inbox with invite emails. The Invite User API accepts automated invitation requests for the same target address without applying a request or per-recipient rate limit. A valid account is required, and sustained requests cause repeated messages that can obscure legitimate mail and disrupt use of the recipient's inbox.

CVSS severity4.3
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper rate limiting in Ascertia SigningHub 8.6.8 and earlier allows remote authenticated users to flood a target inbox with invite emails. The Invite User API accepts automated invitation requests for the same target address without applying a request or per-recipient rate limit. A valid account is required, and sustained requests cause repeated messages that can obscure legitimate mail and disrupt use of the recipient's inbox.

The record

CVE
CVE-2025-54320
Published
Nov 18, 2025
Updated
Nov 19, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, T1667
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 19, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3CISA ADP VulnrichmentCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1667Email Bombing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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