# CVE-2026-56774: Kanboard - Cross-User Deletion of Persistent Login Sessions via Unvalidated Session ID

> Authenticated users can delete other users' persistent login sessions by manipulating session IDs, causing denial of service and forcing re-authentication.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Jun 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-vvjm-mjq4-27c8

## What is CVE-2026-56774?

CVE-2026-56774 is a medium-severity missing authorization vulnerability in kanboard, published on 25 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Kanboard through 1.2.52, fixed in commit 928c68a, UserViewController::removeSession fails to validate the session id parameter before passing it to RememberMeSessionModel::remove, allowing authenticated users to delete other users' Remember Me sessions. Attackers can enumerate sequential session IDs and mass-invalidate persistent login sessions of any user, including administrators, forcing re-authentication and causing denial of service.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-56774?


## How do I fix CVE-2026-56774?

No fix has been published for CVE-2026-56774 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-56774 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56774 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56774 and fix it if it is affected.

What it is: CVE-2026-56774 is a medium-severity missing authorization vulnerability in kanboard, published on 25 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56774 exists.

Affected product: kanboard. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56774/ (Markdown: https://insights.sbomify.com/CVE-2026-56774/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56774
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56774
- OSV: https://osv.dev/vulnerability/CVE-2026-56774

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56774/
Summaries are generated and may contain mistakes; the official description above is the record.