CVE-2026-9811: Mautic/core Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-5hvg-w58j-545m
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CVSS 5.4
CWE-79
Published
Advisory Summary

CVE-2026-9811 is a MODERATE (CVSS 5.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mautic/core libraries in the Packagist ecosystem. The issue involves mautic has stored cross-site scripting (xss) in project option selector. Remediation is available by upgrading affected packages to version 7.1.2.

CVE-2026-9811 at a Glance

CVE Identifier CVE-2026-9811
GHSA Identifier GHSA-5hvg-w58j-545m
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Mautic/core
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-9811

To remediate this vulnerability, upgrade all affected Mautic/core dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mautic/core fixed: 7.1.2 
Upgrade mautic/core to 7.1.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for mautic/core

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-9811, inspect your project dependencies for Mautic/core:

inspect dependencies for mautic/core

Analyze the terminal output to locate any version of Mautic/core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.1.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Mautic/core, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary A stored Cross-Site Scripting (XSS) vulnerability exists in the project selector component of Mautic 7. When rendering selection menus for associating projects with system entities, the application fails to sanitize project names returned via AJAX before injecting them into the DOM as option fields. An authenticated user with permissions to create projects can exploit this to store a malicious script payload in the project's name. ### Impact When another administrative user subsequently opens an entity editor containing the project selector, the injected script executes within the context of their active browser session. This could allow an attacker to hijack the session, perform unauthorized state coordination, or access organizational data within the dashboard. ### Patched Versions This security issue has been addressed in the following release: * **7.1.2** *Note: Mautic 6.x, 5.x, and 4.x branches do not contain the Projects feature or the associated AJAX selector and are not affected by this vulnerability. For general security support regarding legacy Mautic 4 releases, please refer to the [ELTS](https://mautic.org/extended-long-term-support-elts/) page.* ### Workarounds There are no official workarounds. To mitigate this vulnerability without upgrading, restrict project creation and modification permissions to trusted administrative users.

CVE-2026-9811 Affected Mautic/core Versions

1 component(s)
Fixed Versions:
7.1.2
Product / Package Ecosystem Affected Versions Fixed Version
mautic/core
 Packagist
≥ 7.0.0
< 7.1.2
7.1.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mautic/mautic/security/advisories/GHSA-5hvg-w58j-545m
NVD — CVE-2026-9811 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-9811
Mautic/core Source Repository REPOSITORY
https://github.com/mautic/mautic

Frequently Asked Questions

What is CVE-2026-9811?
CVE-2026-9811 is a security vulnerability in Mautic/core involving Mautic has Stored Cross-Site Scripting (XSS) in Project Option Selector under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Mautic/core versions are affected?
Affected versions include releases prior to 7.1.2 across affected packages: mautic/core.
What version fixes CVE-2026-9811?
Upgrading to 7.1.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mautic/core affected?
Yes, mautic/core is affected in releases prior to 7.1.2. Upgrade your dependency to 7.1.2 or later.
What is the CVSS score of CVE-2026-9811?
CVE-2026-9811 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-9811?
CVE-2026-9811 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-9811?
Run the dependency tree command: 'inspect dependencies for mautic/core'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5hvg-w58j-545m",
  "modified" : "2026-07-02T19:49:27Z",
  "published" : "2026-07-02T19:49:27Z",
  "aliases" : [ "CVE-2026-9811" ],
  "summary" : "Mautic has Stored Cross-Site Scripting (XSS) in Project Option Selector",
  "details" : "### Summary\nA stored Cross-Site Scripting (XSS) vulnerability exists in the project selector component of Mautic 7. When rendering selection menus for associating projects with system entities, the application fails to sanitize project names returned via AJAX before injecting them into the DOM as option fields. An authenticated user with permissions to create projects can exploit this to store a malicious script payload in the project's name.\n\n### Impact\nWhen another administrative user subsequently opens an entity editor containing the project selector, the injected script executes within the context of their active browser session. This could allow an attacker to hijack the session, perform unauthorized state coordination, or access organizational data within the dashboard.\n\n### Patched Versions\nThis security issue has been addressed in the following release:\n* **7.1.2**\n\n*Note: Mautic 6.x, 5.x, and 4.x branches do not contain the Projects feature or the associated AJAX selector and are not affected by this vulnerability. For general security support regarding legacy Mautic 4 releases, please refer to the [ELTS](https://mautic.org/extended-long-term-support-elts/) page.*\n\n### Workarounds\nThere are no official workarounds. To mitigate this vulnerability without upgrading, restrict project creation and modification permissions to trusted administrative users.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mautic/core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.1.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mautic/mautic/security/advisories/GHSA-5hvg-w58j-545m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-9811"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mautic/mautic"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-02T19:49:27Z",
    "nvd_published_at" : "2026-05-29T12:16:27Z"
  }
}