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Medium

October CMS stored XSS by authenticated backend user with improper configuration

  • Disclosed: 29.11.2023
  • Updated: 11.10.2026 10:22

Impact

A user with access to the media manager that stores SVG files could create a stored XSS attack against themselves and any other user with access to the media manager when SVG files are supported.

SVG files are supported by default in v3 for convenience; however, this has resulted in multiple mistaken vulnerability reports from security researchers. As per the documentation, if a backend user is not trusted, the advice is to remove the svg extension from the list of supported file types.

Patches

The issue has been patched in v3.5.2 by including an SVG sanister. It is enabled by default for new installations but must be enabled for existing sites in the config/media.php file.

'clean_vectors' => true,

Workarounds

If you cannot upgrade for this patch, follow the pervious advice and remove svg from the supported file types.

References

Credits to:

  • Faris Krivic
  • Okan Kurtulus
  • Aldin Visnjic
  • Bug Shankar

For more information

If you have any questions or comments about this advisory:

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package october/system >= 3.0.0, < 3.5.2 3.5.2

References

CVSS score 5.4/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE)
CWE-79
Platform
Composer
Package
october/system
Disclosed
29.11.2023
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-rvx8-p3xp-fj3p - CC BY 4.0

Vulnerability history: october/system

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (25) in the archive
Total entries
25
First → latest
06.2020 09.2026
Without a fix
0
Exploited in attacks
1

Severity breakdown

  • Critical 1
  • High 8
  • Medium 9
  • Low 7

Disclosures per year

Severity:
  1. October CMS stored XSS by authenticated backend user with improper configuration this entry
    Medium · 5.4 CVE-2023-44383 >= 3.0.0, < 3.5.2 3.5.2
  2. October CMS safe mode bypass using Twig sandbox escape
    Critical · 9.1 CVE-2023-44382 >= 3.0.0, < 3.4.15 3.4.15
  3. October CMS Safe Mode bypass leads to authenticated Remote Code Execution
    High · 7.2 CVE-2022-35944 >= 2.0.0, < 2.2.34, >= 3.0.0, < 3.0.66 2.2.34, 3.0.66
  4. October CMS upload process vulnerable to RCE via Race Condition
    High · 8.1 CVE-2022-24800 < 1.0.476, >= 1.1.0, < 1.1.12, >= 2.0.0, < 2.2.15 1.0.476, 1.1.12, 2.2.15
  5. Authenticated remote code execution in October CMS
    High · 7.2 CVE-2022-21705 < 1.0.474, >= 1.1.0, < 1.1.10, >= 2.0.0, < 2.1.27 1.0.474, 1.1.10, 2.1.27
  6. october/system arbitrary code execution
    High · 8.8 CVE-2021-32650 >= 1.1.0, < 1.1.6, < 1.0.473 1.1.6, 1.0.473
  7. October/System authenticated file write leads to remote code execution
    High · 8.8 CVE-2021-32649 >= 1.1.0, < 1.1.6, < 1.0.473 1.1.6, 1.0.473
  8. Deleted Admin Can Sign In to Admin Interface
    High · 7.2 CVE-2021-41126 >= 2.1.0, < 2.1.12 2.1.12
  9. October CMS auth bypass and account takeover
    High · 7.4 CVE-2021-29487 < 1.0.472, >= 1.1.1, < 1.1.5 1.0.472, 1.1.5
  10. Account Takeover in Octobercms
    High · 8.2 Exploited in attacks CVE-2021-32648 < 1.0.472, >= 1.1.1, < 1.1.5 1.0.472, 1.1.5

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