CVE-2023-37269 Winter CMS vulnerable to stored XSS through privileged upload of SVG file
Privileged users can upload malicious SVGs to execute stored XSS if local storage is used and victims visit the file directly.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-37269?
CVE-2023-37269 is a low-severity cross-site scripting vulnerability in wintercms winter, published on 7 Jul 2023. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2023-37269?
2 open source packages ship an affected version, including wintercms/winter. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
wintercms/winter Packagist | All versions | 1.2.3 |
wintercms/winter Packagist | All versions | 1.2.3 |
Products include Wintercms Winter.
How do I fix CVE-2023-37269?
Upgrade wintercms/winter to 1.2.3 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2023-37269 being exploited?
There is no known exploitation of CVE-2023-37269 in the wild and no public exploit code.
Public exploit code: 1 Exploit-DB entry.
Other vulnerabilities in wintercms winter
- CVE-2026-27591 Winter: Privilege escalation by authenticated backend users
- CVE-2024-54149 Winter CMS Modules allows a sandbox bypass in Twig templates leading to data modification and deletion
- CVE-2022-39357 Winter vulnerable to Prototype Pollution in Snowboard framework
- CVE-2024-29686 Winter CMS Server-Side Template Injection (SSTI) vulnerability
- CVE-2023-52085 Winter CMS Local File Inclusion through Server Side Template Injection
Sources
Also known as GHSA-wjw2-4j7j-6gc3.