# CVE-2026-125339: Winter CMS: CSRF through AJAX handler names reachable as backend page actions


- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 10 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-p2ch-c2c3-4xm5

## What is CVE-2026-125339?

CVE-2026-125339 is a medium-severity vulnerability in wintercms winter, published on 10 Nov 2026. 

### Official description

Winter CMS is a content management system built on the Laravel PHP framework. From 1.0.319 until 1.2.14, Backend\Classes\Controller::actionExists() accepts public handler-shaped methods as page actions, so a top-level GET request can invoke state-changing backend AJAX handlers without a CSRF token. Because backend routes use Route::any, CSRF validation skips GET, and the default SameSite=Lax session cookie is sent on cross-site navigation, an unauthenticated attacker can induce an authorized backend user to follow a link such as /backend/system/eventlogs/index_onEmptyLog. Affected handlers in the backend, CMS, and system modules can truncate logs, reset settings, alter backend user state, or delete CMS templates, while URL path segments can select a target record. This issue is fixed in version 1.2.14.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-125339?

1 open source package ship an affected version, including winter/wn-backend-module.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `winter/wn-backend-module` | Packagist | From 1.0.319 | 1.2.14 |

## How do I fix CVE-2026-125339?

Upgrade winter/wn-backend-module to 1.2.14 or later.

## Is CVE-2026-125339 being exploited?

There is no known exploitation of CVE-2026-125339 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125339 and fix it if it is affected.

What it is: CVE-2026-125339 is a medium-severity vulnerability in wintercms winter, published on 10 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-125339 in the wild and no public exploit code.

Affected packages and fixed versions:
- winter/wn-backend-module (Packagist): affected from 1.0.319; fixed in 1.2.14

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-2026-125339/ (Markdown: https://insights.sbomify.com/CVE-2026-125339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125339
- OSV: https://osv.dev/vulnerability/CVE-2026-125339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125339/
Summaries are generated and may contain mistakes; the official description above is the record.