VulnerabilityPublished 20 Aug 2026Updated 10 Nov 2026

CVE-2026-125341: Winter · Stored XSS through Backend List widget image columns

Affects winter/wn-backend-moduleSource GCVE Database

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Authoritative record:CVE-2026-125341· Low 2.0

Not known to be exploited · CVSS 2.0 Low : upgrade to 1.2.14 when convenient.

Data as of 10 Nov 2026, 22:19 UTC

CVSS 3.1 base score

2.0Low

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	2.0

Patch: Available – fixed in 1.2.14

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: High
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade winter/wn-backend-module to 1.2.14.

Affected software

Product	Affected	Fixed in
Packagistwinter/wn-backend-module	Affected >=1.1.0 <1.2.14	Fixed in 1.2.14

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Impact `Backend\Widgets\Lists::evalImageTypeValue()` interpolated the resolved image URL into a single-quoted `src` attribute without escaping it. Where a list column of type [`image`](https://wintercms.com/docs/v1.2/docs/backend/lists#image) rendered an attacker-influenced value, that value could break out of the attribute and inject arbitrary attributes — including event handlers — into the backend list, executing in the session of whichever backend user viewed it. Winter core ships no `image` list column, so a default installation is unaffected. Exploitation requires a plugin that renders attacker-influenced values through one. The supported [image sources](https://wintercms.com/docs/v1.2/docs/services/image-resizing#available-sources) are plugins, themes, the Media Library, the uploads directory, and `Attach\File` models; an arbitrary external URL is not among them. `ImageResizer::filterGetUrl()` returns the value it was given when it cannot resolve an image, however, so an unsupported value reached the attribute verbatim rather than being rejected. As with previous issues of this kind the severity is limited: an attacker must already be able to store the value, and a backend user must then open the affected list. Note that validating a stored URL was not necessarily sufficient — a payload can survive `filter_var($url, FILTER_VALIDATE_URL)`, since `/` is valid both in a URL path and after a quoted HTML attribute value. ### Patches `evalImageTypeValue()` now escapes the image URL, along with the width and height taken from the column configuration, before interpolating them into the tag. This security issue has been fixed as of **v1.2.14** (commit [`0941c9816181095fe35d58e78e6d0c4a49238967`](https://github.com/wintercms/winter/commit/0941c9816181095fe35d58e78e6d0c4a49238967)). ### Workarounds Apply the commit above to `modules/backend/widgets/Lists.php` manually if you are unable to upgrade to v1.2.14. ### References - https://github.com/wintercms/winter/security/advisories/GHSA-43w4-4j3c-jx29 - https://github.com/wintercms/winter/commit/0941c9816181095fe35d58e78e6d0c4a49238967 Credit to Seungyeon Park ([@sy460129](https://github.com/sy460129)) for reporting the issue. ### For more information If you have any questions or comments about this advisory: - Email us at [hello@wintercms.com](mailto:hello@wintercms.com)

CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
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.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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What to do

Affected software

Description

WeaknessesCWE-79

Technical details

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