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TI-2026-70155 Aliases CVE-2026-62367GHSA-xv7q-fvmc-jx96

Vikunja OIDC email fallback lets attackers take over local accounts

Priority LOW 33CWE-287Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

Vikunja versions from 1.0.0 before 2.4.0 are affected. When an administrator enables the emailfallback option on an OpenID Connect provider, Vikunja links an SSO login to an existing local account using only the email claim, without checking email_verified or requiring the account password (CWE-345). An attacker who holds a token from the configured issuer that carries a victim's email can log in as that victim with a full session, with no interaction from the victim.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Vikunja is an open-source self-hosted task management platform. In versions 1.0.0 through 2.3.0, when an administrator enables the per-provider `emailfallback` option on an OpenID Connect provider, Vikunja links an SSO login to a pre-existing local (username+password) account using only the `email` claim from the IdP. The fallback never checks an `email_verified` (or Microsoft `xms_edov`) signal and never requires the matched account's password. An attacker who can obtain a token from the configured issuer carrying a victim's email logs in as that victim with a full session, with no consent or interaction from the victim. Version 2.4.0 fixes the issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00089 0th percentileScored 2026-11-07
Fix Fixed vikunja (go-vikunja): 2.4.0code.vikunja.io/api (Go): 2.4.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
go-vikunjavikunja1.0.0 to before 2.4.02.4.0Patch availableCNA
—code.vikunja.io/api (Go)1.0.0 to before 2.4.02.4.0Patch availableGHSA-xv7q-fvmc-jx96
  • vikunja Vendorgo-vikunja Affected 1.0.0 to before 2.4.0 Fixed in 2.4.0 Patch available CNA
  • code.vikunja.io/api (Go) Vendor— Affected 1.0.0 to before 2.4.0 Fixed in 2.4.0 Patch available GHSA-xv7q-fvmc-jx96

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*——go-vikunja
  • cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:* Versions — — ·go-vikunja

Remediation

The code.vikunja.io/api Go module is fixed in 2.4.0. The sources list no fixed version for vikunja.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA vikunja (go-vikunja) Fixed in 2.4.0
  • Fix · GHSA-xv7q-fvmc-jx96 code.vikunja.io/api (Go) Fixed in 2.4.0 Advisory →

Timeline

  1. 2026-10-10 Threatist record created from CVE-2026-62367
  2. 2026-10-10 Alias added: GHSA-xv7q-fvmc-jx96
  3. 2026-10-10 Fix available: Go/code.vikunja.io/[email protected] · GHSA-xv7q-fvmc-jx96
  4. 2026-10-10 CVSS score added · GHSA-xv7q-fvmc-jx96
  5. 2026-10-10 Weakness changed · GHSA-xv7q-fvmc-jx96
  6. 2026-10-10 4 new references · GHSA-xv7q-fvmc-jx96
  7. 2026-10-11 Priority changed: MEDIUM → LOW
  8. 2026-10-13 CISA SSVC decision points changed

References

Other 4

  • TI-2026-40929 Authorization bypass in go-vikunja Vikunja CVSS 4.0CRITICAL 9.3
  • TI-2026-21967 Vijkunja has Weak Password Policy Combined with Persistent Sessions After Password Change CVSS 3.1CRITICAL 9.1
  • TI-2026-62115 Vikunja before 2.6.0 Privilege Escalation via Link Share Hash CVSS 4.0HIGH 8.7
  • TI-2026-62108 Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth CVSS 4.0HIGH 8.7
  • TI-2026-62107 Vikunja before 2.6.0 Authentication Bypass via Unthrottled API CVSS 4.0HIGH 8.7
  • TI-2026-26971 Vikunja ahs a TOTP Two-Factor Authentication Bypass via OIDC Login Path CVSS 3.1CRITICAL 9.1
See all 105 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences