Winter CMS: Stored XSS through cached Brand Settings and Editor Settings custom styles
- Exploited
- No known exploitation
- Fix
- Fixed in 1.2.14
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.2.14.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 18/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Winter CMS is a content management system built on the Laravel PHP framework. Prior to 1.2.14, BrandSetting::renderCss() and EditorSetting::renderCss() store raw LESS compiler output with Cache::forever() but apply strip_tags() only to the value returned on a cache miss. The first render after saving custom CSS appears sanitized while priming an unsafe cache entry, and later cache hits return unsanitized output into the backend style element, allowing a user with backend.manage_branding or backend.manage_editor to cause stored cross-site scripting when another backend page renders the styles. The styles also appear on unauthenticated backend sign-in, password restore, and password reset layouts. This issue is fixed in version 1.2.14.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure3/25Reachable over the network · Unknown: No advisory context yet
- Reach10/20Affects Packagist packages
- Severity4.5/10CVSS 4.5
- No patch0/5No signal
What would change the score
- Would score about 73 if added to CISA KEV
- Would score about 68 if CISA's SSVC rates exploitation active
- Would score about 37 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.2.14.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-125338 (Winter CMS: Stored XSS through cached Brand Settings and Editor Settings custom styles), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-125338 (entry last updated 2026-11-10): Affected: - wintercms winter: fixed in 1.2.14 - Packagist package winter/wn-backend-module: fixed in 1.2.14 Fixed versions: 1.2.14. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-125338 is not listed as of cve.now's last read. This KEV status is for CVE-2026-125338 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (Packagist): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/wintercms/winter/security/advisories/GHSA-5cwr-5jxg-pcf6 - https://github.com/wintercms/winter/commit/c95d780ab54f3a3f74a94ae1667bf12b3c549d5d - https://github.com/wintercms/winter/releases/tag/v1.2.14 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-125338 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125338.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- wintercms winter
fixed in 1.2.14
- winter/wn-backend-modulePackagist
fixed in 1.2.14
Evidence 5
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 2
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-125338
Is CVE-2026-125338 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-125338?
winter: before 1.2.14. winter/wn-backend-module (Packagist): before 1.2.14.Source: cve.now feed data
How do I fix CVE-2026-125338?
Upgrade to a fixed version: 1.2.14.Source: cve.now feed data