CVE-2026-115457
baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.1
baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments
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.
- Record
CVE-2026-115457- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-109081
7.1
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.
- Record
EUVD-2026-109081- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N - Updated
- 2026-11-02
NVD
7.1
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.
- Record
CVE-2026-115457- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
7.1
baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments
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.
- Record
CVE-2026-115457- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-115457 is a high vulnerability (CVSS 7.1) in Baserproject Basercms, published October 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. No source names a fixed version.
References
github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x
github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec
github.com/baserproject/basercms/releases/tag/5.3.2
github.com/baserproject/basercms/releases/tag/5.4.2
github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115457.json
nvd.nist.gov/vuln/detail/CVE-2026-115457