CVE-2026-115457 (GCVE-0-2026-115457)

Vulnerability from cvelistv5 – Published: 2026-10-23 14:00 – Updated: 2026-10-23 14:00
VLAI
Title
baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments
Summary
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.
Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7761 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
baserproject basercms Affected: >= 5.0.0, < 5.3.2
Affected: >= 5.4.0, < 5.4.2
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "basercms",
          "vendor": "baserproject",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 5.0.0, \u003c 5.3.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 5.4.0, \u003c 5.4.2"
            }
          ]
        }
      ],
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          "value": "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\u0027s 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N",
            "version": "3.1"
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              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
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              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T14:00:33.254Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x"
        },
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          "name": "https://github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec",
          "tags": [
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          ],
          "url": "https://github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec"
        },
        {
          "name": "https://github.com/baserproject/basercms/releases/tag/5.3.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/baserproject/basercms/releases/tag/5.3.2"
        },
        {
          "name": "https://github.com/baserproject/basercms/releases/tag/5.4.2",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/baserproject/basercms/releases/tag/5.4.2"
        }
      ],
      "source": {
        "advisory": "GHSA-qhv2-3j2q-v43x",
        "discovery": "UNKNOWN"
      },
      "title": "baserCMS: Unauthenticated Stored XSS via Shortcode Expansion in Blog Comments"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-115457",
    "datePublished": "2026-10-23T14:00:33.254Z",
    "dateReserved": "2026-10-22T15:06:52.736Z",
    "dateUpdated": "2026-10-23T14:00:33.254Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-115457",
      "date": "2026-10-25",
      "epss": "0.00295",
      "percentile": "0.21982"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "basercms",
                "vendor": "baserproject",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003e= 5.0.0, \u003c 5.3.2"
                  },
                  {
                    "status": "affected",
                    "version": "\u003e= 5.4.0, \u003c 5.4.2"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "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\u0027s 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."
          }
        ],
        "id": "CVE-2026-115457",
        "lastModified": "2026-10-23T16:28:32.357",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 4.2,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
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        },
        "published": "2026-10-23T14:17:51.867",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/baserproject/basercms/commit/bec4776ab497457fac76da7ae67d2dd0ad964eec"
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            "source": "security-advisories@github.com",
            "url": "https://github.com/baserproject/basercms/releases/tag/5.3.2"
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            "source": "security-advisories@github.com",
            "url": "https://github.com/baserproject/basercms/releases/tag/5.4.2"
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            "source": "security-advisories@github.com",
            "url": "https://github.com/baserproject/basercms/security/advisories/GHSA-qhv2-3j2q-v43x"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
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            "description": [
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              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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