CVE-2025-2123 — geshi/geshi
CVE-2025-2123 is a Cross-site Scripting (XSS) vulnerability in geshi/geshi. No vendor fix is recorded yet; mitigation options are listed below.
GeSHi CSS cssgen.php get_var cross site scripting
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-2123.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
geshi/geshiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | geshi/geshi | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for geshi/geshi, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of geshi/geshi has shipped for CVE-2025-2123 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-2123 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-2123. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-2123 in your dependencies?
O3 Security finds CVE-2025-2123 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.