PT-2026-31944 · Vikunja · Vikunja

Published 2026-04-10 · Updated 2026-04-10 · CVE-2026-34727

Positive Technologies (AI Summary)

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Name of the Vulnerable Software and Affected Versions: Vikunja versions prior to 2.3.0

Description: A flaw exists in the OIDC callback handler where a full JWT token is issued without verifying TOTP two-factor authentication status for the matched user. Specifically, when a local user with TOTP enabled is matched via the OIDC email fallback mechanism, the second factor is bypassed. This allows an attacker who can authenticate to the OIDC provider with a matching email address to gain full access without a second-factor challenge, undermining the security of TOTP enrollment. This issue is a prerequisite for an OIDC email fallback account takeover, potentially allowing bypass of both password and TOTP second factor authentication.

Recommendations: Update to version 2.3.0 or later. As a mitigation, add a TOTP check in the OIDC callback before issuing the JWT.

Exploit

Fix

Improper Authentication

Weakness Enumeration

CWE-287

Related Identifiers

CVE-2026-34727

GHSA-8JVC-MCX6-R4CG

Affected Products

Vikunja

References · 9

• 🔥 https://github.com/go-vikunja/vikunja/security/advisories/GHSA-8jvc-mcx6-r4cg · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-34727 · Security Note
• https://osv.dev/vulnerability/GHSA-8jvc-mcx6-r4cg · Vendor Advisory
• https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0 · Note
• https://github.com/go-vikunja/vikunja · Note
• https://github.com/go-vikunja/vikunja/commit/b642b2a4536a3846e627a78dce2fdd1be425e6a1 · Note
• https://github.com/go-vikunja/vikunja/pull/2582 · Note
• https://twitter.com/infoflowcloud/status/2042710861999902925 · Twitter Post
• https://twitter.com/CVEnew/status/2042710280501629341 · Twitter Post