# CVE-2024-55603: Insufficient session invalidation in Kanboard

> Attackers can reuse expired sessions to maintain unauthorized access to Kanboard accounts due to insufficient session invalidation checks.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Dec 2024
- **Updated:** 20 Dec 2024
- **Also known as:** GHSA-gv5c-8pxr-p484

## What is CVE-2024-55603?

CVE-2024-55603 is a medium-severity authentication bypass vulnerability in kanboard, published on 18 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Kanboard is project management software that focuses on the Kanban methodology. In affected versions sessions are still usable even though their lifetime has exceeded. Kanboard implements a cutom session handler (`app/Core/Session/SessionHandler.php`), to store the session data in a database. Therefore, when a `session_id` is given, kanboard queries the data from the `sessions` sql table. At this point, it does not correctly verify, if a given `session_id` has already exceeded its lifetime (`expires_at`).
Thus, a session which's lifetime is already `> time()`, is still queried from the database and hence a valid login. The implemented **SessionHandlerInterface::gc** function, that does remove invalid sessions, is called only **with a certain probability** (_Cleans up expired sessions. Called by `session_start()`, based on `session.gc_divisor`, `session.gc_probability` and `session.gc_maxlifetime` settings_) accordingly to the php documentation. In the official Kanboard docker image these values default to: session.gc_probability=1, session.gc_divisor=1000. Thus, an expired session is only terminated with probability 1/1000. This issue has been addressed in release 1.2.43 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2024-55603?

It affects 1 product.


Products: Kanboard Kanboard.

## How do I fix CVE-2024-55603?

No fix has been published for CVE-2024-55603 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-55603 being exploited?

There is no known exploitation of CVE-2024-55603 in the wild and no public exploit code.

## Other vulnerabilities in kanboard

- [CVE-2026-21881](https://insights.sbomify.com/CVE-2026-21881/): Kanboard is Vulnerable to Reverse Proxy Authentication Bypass (critical 9.1)
- [CVE-2025-55010](https://insights.sbomify.com/CVE-2025-55010/): Kanboard Authenticated Admin Remote Code Execution via Unsafe Deserialization of Events (critical 9.1)
- [CVE-2024-51747](https://insights.sbomify.com/CVE-2024-51747/): Arbitrary File Read and Delete in kanboard (critical 9.1)
- [CVE-2024-51748](https://insights.sbomify.com/CVE-2024-51748/): Remote code execution through language setting in kanboard (critical 9.1)
- [CVE-2017-12850](https://insights.sbomify.com/CVE-2017-12850/): Business logic in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-55603 and fix it if it is affected.

What it is: CVE-2024-55603 is a medium-severity authentication bypass vulnerability in kanboard, published on 18 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-55603 in the wild and no public exploit code.

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-2024-55603/ (Markdown: https://insights.sbomify.com/CVE-2024-55603/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-55603
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-55603
- OSV: https://osv.dev/vulnerability/CVE-2024-55603

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-55603/
Summaries are generated and may contain mistakes; the official description above is the record.