High 7.1Published Oct 23, 2026

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

Updated under an hour ago (Oct 27, 2026, 11:10 PM ET)

Does this affect you?

It affects baserproject basercms. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.29%, higher than 22% of scored CVEs.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for baserproject basercms

Exploited in the last 30 days

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: 7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.29% (percentile 22)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 23, 2026
First seen by InfoSec Signals: Oct 23, 2026

Affected products

Affected products

baserproject basercms baserproject:basercms (from the name)	from 5.0.0, < 5.3.2; from 5.4.0, < 5.4.2	CNA record

References

References

https://github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x	x-refsource-confirm
https://github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec	x-refsource-misc
https://github.com/baserproject/basercms/releases/tag/5.3.2	x-refsource-misc
https://github.com/baserproject/basercms/releases/tag/5.4.2	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.