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Fencer Intel
medium 4.3

CVE-2026-123518 json

Vikunja before 2.7.1 Missing Authorization in Kanban Task-Bucket Move

published 21d ago modified 2d ago also EUVD-2026-119403 , GHSA-w64q-7p4m-j8g8

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository go-vikunja/vikunja. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

Vikunja before 2.7.1 contains an incorrect authorization vulnerability in TaskBucket.CanUpdate, which checks write access to the bucket's project and to the task separately but never verifies that both belong to the same project. Authenticated users with write access to two projects can move a task into another project's kanban bucket. This persists cross-project task_buckets rows that count toward bucket limits and, for done buckets, toggle the task's done state.

Patch / fix

  • go-vikunja vikunja 2.7.1

Is CVE-2026-123518 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2d ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w64q-7p4m-j8g8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • go-vikunja vikunja

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of go-vikunja/vikunja published their own advisory on GitHub. Reviewed sources take precedence over it.