CVE-2026-115457
baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments
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CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
Attack conditions and impact
Derived from the CNA (via NVD) CVSS 3.1 vector| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Privileges required PR | N | None |
| User interaction UI | R | Required |
| Scope S | U | Unchanged |
| Confidentiality C | H | High |
| Integrity I | L | Low |
| Availability A | N | None |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
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.
CVSS assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / [email protected] (Secondary) | 3.1 | 7.1 HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N |
| CNA / GitHub_M | 3.1 | 7.1 HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| baserproject | basercms | affected: >= 5.0.0, < 5.3.2 affected: >= 5.4.0, < 5.4.2 |
Linux distribution status
References (4)
- https://github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec NVD, CNA x_refsource_MISC
- https://github.com/baserproject/basercms/releases/tag/5.3.2 NVD, CNA x_refsource_MISC
- https://github.com/baserproject/basercms/releases/tag/5.4.2 NVD, CNA x_refsource_MISC
- https://github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x NVD, CNA x_refsource_CONFIRM