CVE-2026-91972Public exploitNetwork attack vectorHinoki check available

Authentication-control bypass via omitted pre-auth rate limiter

Published Sep 15, 2026 · Updated Sep 15, 2026

Improper authentication-attempt restriction in Vikunja before 2.6.0 allows remote attackers to make unthrottled API requests. The registerAPIRoutesV2 function attaches unauthRateLimit() only to /api/v2/ws, leaving public login, registration, password-reset, and OAuth token routes governed solely by the disabled-by-default configurable limiter. A default installation therefore permits unauthenticated credential guessing, account enumeration, and password-reset flooding without the v1 API's per-IP floor.

CVSS severityUnavailable
Unscored
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Improper authentication-attempt restriction in Vikunja before 2.6.0 allows remote attackers to make unthrottled API requests. The registerAPIRoutesV2 function attaches unauthRateLimit() only to /api/v2/ws, leaving public login, registration, password-reset, and OAuth token routes governed solely by the disabled-by-default configurable limiter. A default installation therefore permits unauthenticated credential guessing, account enumeration, and password-reset flooding without the v1 API's per-IP floor.

The record

CVE
CVE-2026-91972
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Vikunja
Product
Vikunja
Classifications
CWE-307, CAPEC-49, T1110.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 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 <2.6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vikunja · Vikunjaversion=0 <2.6.0

Published CVSS scores

No CVSS assessment is available in this record.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
CAPEC-49Password Brute Forcing
T1110.001Password Guessing

Public exploit references

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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