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Fencer Vulns
low 2.0

CVE-2023-37269 json

Winter CMS vulnerable to stored XSS through privileged upload of SVG file

published 2023-07-07 3 y ago modified 2026-09-10 1 mo ago also GHSA-wjw2-4j7j-6gc3 , EUVD-2023-2167

cvss
2.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 86%
public exploits
1
Exploit-DB

Summary

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Users with the `backend.manage_branding` permission can upload SVGs as the application logo. Prior to version 1.2.3, SVG uploads were not sanitized, which could have allowed a stored cross-site scripting (XSS) attack. To exploit the vulnerability, an attacker would already need to have developer or super user level permissions in Winter CMS. This means they would already have extensive access and control within the system. Additionally, to execute the XSS, the attacker would need to convince the victim to directly visit the URL of the maliciously uploaded SVG, and the application would have to be using local storage where uploaded files are served under the same domain as the application itself instead of a CDN. This is because all SVGs in Winter CMS are rendered through an `img` tag, which prevents any payloads from being executed directly. These two factors significantly limit the potential harm of this vulnerability. This issue has been patched in v1.2.3 through the inclusion of full support for SVG uploads and automatic sanitization of uploaded SVG files. As a workaround, one may apply the patches manually.

Patch / fix

  • packagist wintercms/winter 1.2.3
  • wintercms winter 1.2.3

Timeline

  1. Published
  2. First public exploit (EDB-51591)

Exploit prediction

2.70% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-51591 WinterCMS < 1.2.3 - Persistent Cross-Site Scripting webapps, 2023-07-15
  • packetstormsecurity.com http://packetstormsecurity.com/files/173520/WinterCMS-1.2.2-Cross-Site-Scripting.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 2.0 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 2.0 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist wintercms/winter
<1.2.3
1.2.3

Affected products

  • wintercms winter

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.