5.3

CVE-2026-91981: go-vikunja vikunja

CVSS: 5.3v4.0MediumDeferred
AliasesGHSA-vfxw-3x8p-2vjrGO-2026-6752
Published 15-09-2026Last modified 21-09-2026
Open JSON

Vulnerability summary

CVE-2026-91981 is a medium (CVSS 5.3) vulnerability in go-vikunja vikunja. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.1% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.31%
0%100%
Low · +0.07 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 15-09-2026
    PublishedVulnerability first disclosed.
  2. 21-09-2026
    Last modifiedVulnerability information updated.

Description

Vikunja versions before 2.6.0 fail to properly validate link-share tokens in the v2 API user search endpoints. Attackers with a read-only share link can enumerate project users via the projects endpoint and confirm arbitrary usernames exist via the global search endpoint.

CVSS metrics

5 scores · 3 sources · 2 versions

EPSS trend

Probability

0.31%

Chance of exploitation in the next 30 days

Percentile

22%

Versus all other CVEs

30-day change

+0.07 pp

From 0.24% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.31%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Code.vikunja.io1 product
  • api< 2.6.0 | All versions (No fix recorded)
Go-vikunja1 product

2 vendors · 2 products

References

6 links