CVE-2026-54766Public exploitNetwork attack vectorHinoki check available

Cross-tenant content injection via parent authorization bypass

Published Aug 28, 2026 · Updated Aug 28, 2026

Incorrect authorization in Vikunja 0.21.0 through 2.3.0 allows remote authenticated users to inject projects into another tenant's hierarchy. ProjectDuplicate.CanCreate passes an unhydrated target parent to CanCreate instead of invoking CanWrite, causing the write-permission branch to be skipped. An attacker needs an account and read access to the source project; the operation adds attacker-owned content but does not alter or disclose existing victim data.

CVSS severity5.3
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Incorrect authorization in Vikunja 0.21.0 through 2.3.0 allows remote authenticated users to inject projects into another tenant's hierarchy. ProjectDuplicate.CanCreate passes an unhydrated target parent to CanCreate instead of invoking CanWrite, causing the write-permission branch to be skipped. An attacker needs an account and read access to the source project; the operation adds attacker-owned content but does not alter or disclose existing victim data.

The record

CVE
CVE-2026-54766
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Vikunja
Product
Vikunja
Classifications
CWE-285, CWE-863, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 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=>= 0.21.0, < 2.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Vikunja · Vikunjaversion=>= 0.21.0, < 2.4.0

Published CVSS scores

5.3GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-863Incorrect Authorization
T1565.001Stored Data Manipulation

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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