# CVE-2021-26544: Apache Livy (Incubating) is vulnerable to cross site scripting

> A cross-site scripting vulnerability in Apache Livy allows attackers to access other users' session logs and execute jobs with their privileges.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Feb 2021
- **Updated:** 13 Feb 2025
- **Also known as:** GHSA-74qp-233x-p5j8

## What is CVE-2021-26544?

CVE-2021-26544 is a medium-severity cross-site scripting vulnerability in Apache Livy (Incubating), published on 20 Feb 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Livy server version 0.7.0-incubating (only) is vulnerable to a cross site scripting issue in the session name. A malicious user could use this flaw to access logs and results of other users' sessions and run jobs with their privileges. This issue is fixed in Livy 0.7.1-incubating.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-26544?

2 open source packages ship an affected version, including org.apache.livy:livy-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.livy:livy-server` | Maven | From 0.7.0-incubating | 0.7.1-incubating |
| `org.apache.livy:livy-server` | Maven | From 0.7.0-incubating | 0.7.1-incubating |

Products: Apache Livy.

## How do I fix CVE-2021-26544?

Upgrade org.apache.livy:livy-server to 0.7.1-incubating or later.

## Is CVE-2021-26544 being exploited?

There is no known exploitation of CVE-2021-26544 in the wild and no public exploit code.

## Other vulnerabilities in Apache Livy (Incubating)

- [CVE-2025-60012](https://insights.sbomify.com/CVE-2025-60012/): Apache Livy: Restrict file access (medium 6.3)
- [CVE-2025-66249](https://insights.sbomify.com/CVE-2025-66249/): Apache Livy: Unauthorized directory access (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26544 and fix it if it is affected.

What it is: CVE-2021-26544 is a medium-severity cross-site scripting vulnerability in Apache Livy (Incubating), published on 20 Feb 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-26544 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.livy:livy-server (Maven): affected from 0.7.0-incubating; fixed in 0.7.1-incubating
- org.apache.livy:livy-server (Maven): affected from 0.7.0-incubating; fixed in 0.7.1-incubating

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-2021-26544/ (Markdown: https://insights.sbomify.com/CVE-2021-26544/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26544
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26544
- OSV: https://osv.dev/vulnerability/CVE-2021-26544

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26544/
Summaries are generated and may contain mistakes; the official description above is the record.