# CVE-2021-26081: Information disclosure in Jira Data Center

> Remote attackers can enumerate usernames via a sensitive data exposure flaw in the Jira REST API temporary avatar endpoint.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:** 20 Jul 2021
- **Updated:** 11 Oct 2024
- **Also known as:** GHSA-v3g7-jggh-wjhg

## What is CVE-2021-26081?

CVE-2021-26081 is a medium-severity vulnerability in Atlassian Jira, published on 20 Jul 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

REST API in Atlassian Jira Server and Jira Data Center before version 8.5.14, from version 8.6.0 before 8.13.6, and from version 8.14.0 before 8.16.1 allows remote attackers to enumerate usernames via a Sensitive Data Exposure vulnerability in the `/rest/api/latest/user/avatar/temporary` endpoint.

## Which versions are affected by CVE-2021-26081?

It affects 4 products.


Products: Atlassian Data Center, Atlassian Jira, Atlassian Jira Data Center, Atlassian Jira Server.

## How do I fix CVE-2021-26081?

No fix has been published for CVE-2021-26081 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26081 being exploited?

There is no known exploitation of CVE-2021-26081 in the wild and no public exploit code.

## Other vulnerabilities in Atlassian Jira

- [CVE-2017-18113](https://insights.sbomify.com/CVE-2017-18113/): Code injection in Jira Data Center (high 8.8)
- [CVE-2021-41312](https://insights.sbomify.com/CVE-2021-41312/): Auth bypass in Jira Data Center (high 7.5)
- [CVE-2021-39123](https://insights.sbomify.com/CVE-2021-39123/): Denial of service in Jira Data Center (high 7.5)
- [CVE-2021-39113](https://insights.sbomify.com/CVE-2021-39113/): Missing authorization in Jira Data Center (high 7.5)
- [CVE-2021-43947](https://insights.sbomify.com/CVE-2021-43947/): Code injection in Jira Data Center (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26081 and fix it if it is affected.

What it is: CVE-2021-26081 is a medium-severity vulnerability in Atlassian Jira, published on 20 Jul 2021. 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-2021-26081 in the wild and no public exploit code.

Affected product: Atlassian Jira. 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-2021-26081/ (Markdown: https://insights.sbomify.com/CVE-2021-26081/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26081
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26081
- OSV: https://osv.dev/vulnerability/CVE-2021-26081

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26081/
Summaries are generated and may contain mistakes; the official description above is the record.