# CVE-2025-2123: GeSHi CSS cssgen.php get_var cross site scripting

> Attackers can inject malicious scripts via CSS generation parameters in GeSHi, potentially executing code in user browsers.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 9 Mar 2025
- **Updated:** 10 Mar 2025
- **Also known as:** DEBIAN-CVE-2025-2123, GHSA-pr6q-g5gv-qgr7, UBUNTU-CVE-2025-2123

## What is CVE-2025-2123?

CVE-2025-2123 is a medium-severity cross-site scripting vulnerability in GeSHi, published on 9 Mar 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

A vulnerability, which was classified as problematic, has been found in GeSHi up to 1.0.9.1. Affected by this issue is the function get_var of the file /contrib/cssgen.php of the component CSS Handler. The manipulation of the argument default-styles/keywords-1/keywords-2/keywords-3/keywords-4/comments leads to cross site scripting. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-2123?

2 open source packages ship an affected version, including geshi/geshi. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `geshi/geshi` | Packagist | All versions to 1.0.9.1 | None |
| `geshi/geshi` | Packagist | All versions to 1.0.9.1 | None |

Products: Qbnz Geshi.

## How do I fix CVE-2025-2123?

Upgrade to a fixed version.

## Is CVE-2025-2123 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-2123 exists.

## Other vulnerabilities in GeSHi

- [CVE-2012-3521](https://insights.sbomify.com/CVE-2012-3521/): GeSHi vulnerable to Directory Traversal (medium 5.0)
- [CVE-2012-3522](https://insights.sbomify.com/CVE-2012-3522/): GeSHi vulnerable to Cross-site Scripting (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-2123 and fix it if it is affected.

What it is: CVE-2025-2123 is a medium-severity cross-site scripting vulnerability in GeSHi, published on 9 Mar 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-2123 exists.

Affected packages and fixed versions:
- geshi/geshi (Packagist): affected all versions up to 1.0.9.1; no fix listed
- geshi/geshi (Packagist): affected all versions up to 1.0.9.1; no fix listed

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-2025-2123/ (Markdown: https://insights.sbomify.com/CVE-2025-2123/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-2123
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-2123
- OSV: https://osv.dev/vulnerability/CVE-2025-2123

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-2123/
Summaries are generated and may contain mistakes; the official description above is the record.