# CVE-2018-20238: Auth bypass in Crowd

> Remote attackers can authenticate using expired user sessions in Atlassian Crowd, leading to unauthorized account access.

- **Severity:** High 8.1 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A: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:** 13 Feb 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-jj3c-2ggq-fxgg

## What is CVE-2018-20238?

CVE-2018-20238 is a high-severity authentication bypass vulnerability in Atlassian Crowd, published on 13 Feb 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Various rest resources in Atlassian Crowd before version 3.2.7 and from version 3.3.0 before version 3.3.4 allow remote attackers to authenticate using an expired user session via an insufficient session expiration vulnerability.

Weakness: CWE-384 (Session Fixation)

## Which versions are affected by CVE-2018-20238?

It affects 1 product.


Products: Atlassian Crowd.

## How do I fix CVE-2018-20238?

No fix has been published for CVE-2018-20238 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-20238 being exploited?

There is no known exploitation of CVE-2018-20238 in the wild and no public exploit code.

## Other vulnerabilities in Atlassian Crowd

- [CVE-2019-11580](https://insights.sbomify.com/CVE-2019-11580/): Atlassian Crowd and Crowd Data Center Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-43782](https://insights.sbomify.com/CVE-2022-43782/): Auth bypass in Crowd Data Center (critical 9.8)
- [CVE-2016-6496](https://insights.sbomify.com/CVE-2016-6496/): Deserialization in n/a (critical 9.8)
- [CVE-2017-18105](https://insights.sbomify.com/CVE-2017-18105/): Auth bypass in Crowd (high 8.1)
- [CVE-2023-22521](https://insights.sbomify.com/CVE-2023-22521/): Code injection in Crowd Data Center (high 8.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20238 and fix it if it is affected.

What it is: CVE-2018-20238 is a high-severity authentication bypass vulnerability in Atlassian Crowd, published on 13 Feb 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-20238 in the wild and no public exploit code.

Affected product: Atlassian Crowd. 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-2018-20238/ (Markdown: https://insights.sbomify.com/CVE-2018-20238/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20238
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20238
- OSV: https://osv.dev/vulnerability/CVE-2018-20238

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20238/
Summaries are generated and may contain mistakes; the official description above is the record.