# CVE-2026-115457: baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments


- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 23 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-qhv2-3j2q-v43x

## What is CVE-2026-115457?

CVE-2026-115457 is a high-severity vulnerability in baserproject basercms, published on 23 Oct 2026. 

### Official description

baserCMS is a website development framework. In versions 5.0.0 before 5.3.2 and 5.4.0 before 5.4.2, global shortcode expansion runs over the complete rendered page, including HTML-escaped blog comments supplied by unauthenticated visitors. A comment containing the BcBaser.getGoogleMaps shortcode can set apiBaseUrl to an attacker-controlled script URL, which is emitted as a script src and executes JavaScript on the site's origin when another visitor or administrator opens the article displaying that comment. Escaping raw HTML in comments does not prevent this stored cross-site scripting because shortcode processing happens after HTML rendering. Other registered shortcodes also expand in comments; Mail.getForm can embed a working contact form with a valid CSRF token. The flaw can compromise the authenticated browser context of an administrator who views the affected article. This issue has been patched in versions 5.3.2 and 5.4.2.

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

## Which versions are affected by CVE-2026-115457?


## How do I fix CVE-2026-115457?

No fix has been published for CVE-2026-115457 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-115457 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-115457 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-115457 and fix it if it is affected.

What it is: CVE-2026-115457 is a high-severity vulnerability in baserproject basercms, published on 23 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-115457 exists.

Affected product: baserproject basercms. 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-2026-115457/ (Markdown: https://insights.sbomify.com/CVE-2026-115457/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-115457
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-115457
- OSV: https://osv.dev/vulnerability/CVE-2026-115457

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-115457/
Summaries are generated and may contain mistakes; the official description above is the record.