CVE-2026-17520Network attack vectorHinoki check available

Unauthenticated privileged API access via predictable key

Published Aug 29, 2026 · Updated Aug 29, 2026

Insufficient API key randomness in Tribulant Software Newsletters before 4.17 allows remote attackers to invoke privileged API actions. The optional API's key generator derives its credential from a publicly known value, making the credential computable instead of unpredictable. Exposure requires the optional API to be enabled; a computed key permits subscriber addition or deletion and newsletter email sending.

CVSS severity4.8
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Insufficient API key randomness in Tribulant Software Newsletters before 4.17 allows remote attackers to invoke privileged API actions. The optional API's key generator derives its credential from a publicly known value, making the credential computable instead of unpredictable. Exposure requires the optional API to be enabled; a computed key permits subscriber addition or deletion and newsletter email sending.

The record

CVE
CVE-2026-17520
Published
Aug 29, 2026
Updated
Aug 29, 2026
Vendor
Tribulant Software
Product
Newsletters
Classifications
CWE-326, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <4.17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tribulant Software · Newslettersversion=0 <4.17

Published CVSS scores

4.8CISA ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-326Inadequate Encryption Strength
T1078Valid Accounts

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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