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Fencer Vulns
medium 5.4

CVE-2026-35600 json

Vikunja has HTML Injection via Task Titles in Overdue Email Notifications

published 2026-04-10 6 mo ago modified 2026-10-26 13 d ago also GHSA-45q4-x4r9-8fqj , GO-2026-5111 , EUVD-2026-21427

cvss
5.4
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 10%
public exploits
0
none known

Summary

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, task titles are embedded directly into Markdown link syntax in overdue email notifications without escaping Markdown special characters. When rendered by goldmark and sanitized by bluemonday (which allows <a> and <img> tags), injected Markdown constructs produce phishing links and tracking pixels in legitimate notification emails. This vulnerability is fixed in 2.3.0.

Patch / fix

  • go code.vikunja.io/api 2.3.0
  • vikunja vikunja 2.3.0
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/go-vikunja/vikunja/security/advisories/GHSA-45q4-x4r9-8fqj referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go code.vikunja.io/api
<2.3.0
all versions
2.3.0

Affected products

  • go-vikunja vikunja

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns 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.