TI-2026-27576 Aliases CVE-2026-35445 GHSA-j5jq-cr68-v2xx

Winter: Authenticated backend users can bypass Users controller permission checks

LOW 32CWE-285Published 2026-08-26 · Updated 2026-08-26

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: Security bypass
Confidentiality · integrity · availability: High · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-285.

Summary

Winter CMS is a content management system built on the Laravel PHP framework. In versions prior to 1.2.13, the backend did not validate the handler name submitted through the form postback _handler POST field, allowing an authenticated backend user to invoke arbitrary controller methods, including protected, private, and action-prefixed ones. While AJAX requests validate that handler names match the on[A-Z][\w+]* pattern, the postback path passed the submitted _handler value straight to the handler dispatcher with no such check, so any controller that exposes a public action or conditionally relaxes its $requiredPermissions check could be reached, bypassing the roles and permissions system. The built-in Users controller was affected because it set $requiredPermissions to null for the myaccount action, letting any authenticated backend user invoke user-management methods such as update_onDelete and update_onManualPasswordReset without holding the backend.manage_users permission. This issue is fixed in version 1.2.13.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00439 38th percentileScored 2026-11-07

Fix Fixed winter (wintercms): 1.2.13winter/wn-backend-module (Packagist): 1.2.13

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
wintercms	winter	before 1.2.13	1.2.13	Patch available	CNA
—	winter/wn-backend-module (Packagist)	before 1.2.13	1.2.13	Patch available	GHSA-j5jq-cr68-v2xx

winter Vendorwintercms Affected before 1.2.13 Fixed in 1.2.13 Patch available CNA
winter/wn-backend-module (Packagist) Vendor— Affected before 1.2.13 Fixed in 1.2.13 Patch available GHSA-j5jq-cr68-v2xx

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:wintercms:winter::::::::	—	—	wintercms

cpe:2.3:a:wintercms:winter:*:*:*:*:*:*:*:* Versions — — ·wintercms

Remediation

Fix · CNA winter (wintercms) Fixed in 1.2.13
Fix · GHSA-j5jq-cr68-v2xx winter/wn-backend-module (Packagist) Fixed in 1.2.13 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-35445
2026-10-03 Alias added: GHSA-j5jq-cr68-v2xx

References

Other 4

TI-2024-19497 Server-side Template Injection (SSTI) vulnerability in Winter CMS v.1.2.3 allows a remote… CVSS 3.1HIGH 7.2
TI-2023-28528 Winter CMS Local File Inclusion through Server Side Template Injection CVSS 3.1MEDIUM 5.4
TI-2022-18732 Winter vulnerable to Prototype Pollution in Snowboard framework CVSS 3.1CRITICAL 9.8
TI-2026-55251 Winter CMS before 1.2.13 Twig Sandbox Escape via SecurityPolicy CVSS 4.0CRITICAL 9.3
TI-2026-21979 Winter: Privilege escalation by authenticated backend users CVSS 3.1CRITICAL 10.0
TI-2024-21102 Dusk plugin may allow unfettered user authentication in misconfigured installs CVSS 3.1HIGH 8.8

See all 18 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences