How severe is CVE-2026-33312?

No CVSS score has been assigned to CVE-2026-33312 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-33312?

CVE-2026-33312 affects the following packages: code.vikunja.io/api (Go). Ecosystems affected: Go.

How do I fix CVE-2026-33312?

Update code.vikunja.io/api to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33312 is resolved across your whole dependency graph.

How do I detect CVE-2026-33312 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code.vikunja.io/api, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-33312 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-33312 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-33312 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-33312?

CVE-2026-33312 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 12th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-33312?

CVE-2026-33312 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-33312 published, and has it been updated?

CVE-2026-33312 was published on March 20, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-33312 — api

CVE-2026-33312 is a CWE-863 vulnerability in code.vikunja.io/api. A fix is available for code.vikunja.io/api — see the affected versions and patch details below.

Read-only Vikunja users can delete project background images via broken object-level authorization

Also known asGHSA-564f-wx8x-878hGO-2026-4795

Published

Mar 20, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33312.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk-0.09%

Lower risk than most CVEs12th percentile — riskier than 12% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹code.vikunja.io/api

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The DELETE /api/v1/projects/:project/background endpoint checks CanRead permission instead of CanUpdate, allowing any user with read-only access to a project to permanently delete its background image.

Details

The RemoveProjectBackground handler (pkg/modules/background/handler/background.go) reuses checkProjectBackgroundRights, a helper originally written for the read-only GetProjectBackground endpoint. This helper only verifies CanRead permission. In contrast, the handler for setting a background (setBackgroundPreparations) correctly checks CanUpdate.

As a result, destructive write operations (deleting the background file from storage and clearing the project's background_file_id and background_blur_hash fields) are gated behind a read-only permission check.

Impact

A user with read-only access to a project — via direct sharing, team membership, link share tokens with read permission, or read-scoped API tokens — can permanently delete the project's background image. The background file is removed from storage and cannot be recovered. This constitutes unauthorized data destruction.

Reproduction

User A creates a project and sets a background image.
User A shares the project with User B with read-only permission.
User B sends: DELETE /api/v1/projects/{project_id}/background with a valid auth token.
The request succeeds. The background image is permanently deleted.

References

pkg/modules/background/handler/background.go — RemoveProjectBackground (line 416), checkProjectBackgroundRights (line 304), setBackgroundPreparations (line 106)
pkg/routes/routes.go line 665 — route registration

Credits

This vulnerability was found using GitHub Security Lab Taskflows.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`code.vikunja.io/api`	≥ 0.20.2&&< 2.2.0	2.2.0`go get code.vikunja.io/api@v2.2.0`

Affected Products

1 product · 1 configurations

Application

vikunjavikunja

≥ 0.20.2 && < 2.2.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code.vikunja.io/api, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update code.vikunja.io/api to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33312 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

## Summary The `DELETE /api/v1/projects/:project/background` endpoint checks `CanRead` permission instead of `CanUpdate`, allowing any user with read-only access to a project to permanently delete its background image. ## Details The `RemoveProjectBackground` handler (`pkg/modules/background/handler/background.go`) reuses `checkProjectBackgroundRights`, a helper originally written for the read-only `GetProjectBackground` endpoint. This helper only verifies `CanRead` permission. In contrast, the handler for *setting* a background (`setBackgroundPreparations`) correctly checks `CanUpdate`. A

O3 Security · Impact-Aware SCA

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