CVE-2026-56765Public exploitNetwork attack vector

Instance-wide attachment theft and deletion via authorization bypass

Published Jul 10, 2026 · Updated Jul 10, 2026

Improper authorization in Vikunja before 2.2.1 allows remote attackers with a link-share URL to read or delete all instance attachments. LinkSharing.ReadAll returns share hashes after clearing only passwords, and GetTaskAttachment authorizes the URL task before fetching a sequential attachment ID without checking task ownership. A public link-share URL is enough to enter the chain; cross-project reads need an accessible task, while deletion also needs a disclosed admin share.

CVSS severity9.3
Critical
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Vikunja before 2.2.1 allows remote attackers with a link-share URL to read or delete all instance attachments. LinkSharing.ReadAll returns share hashes after clearing only passwords, and GetTaskAttachment authorizes the URL task before fetching a sequential attachment ID without checking task ownership. A public link-share URL is enough to enter the chain; cross-project reads need an accessible task, while deletion also needs a disclosed admin share.

The record

CVE
CVE-2026-56765
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
Vikunja
Product
Vikunja
Classifications
CWE-639, T1552, T1213
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 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 <2.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vikunja · Vikunjaversion=0 <2.2.1

Published CVSS scores

9.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1552Unsecured Credentials
T1213Data from Information Repositories

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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