Is CVE-2026-27591 in the CISA KEV catalog?

No. CVE-2026-27591 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27591?

CVE-2026-27591 has a CVSS v3 base score of 9.9 (CRITICAL).

What is the EPSS score for CVE-2026-27591?

CVE-2026-27591 has an EPSS score of 0.49% (39th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27591?

Upgrade winter to 1.2.12 or later.

CVE & CISA-KEV Catalog

CVE-2026-27591

CRITICAL

9.9

CVSS v3

NVD

Description

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.

CWE-284Improper Access Control CWE-639Authorization Bypass Through User-Controlled Key CWE-915

How to fix

Remediation Available

winterNVD

Affected:>= 1.2.0, < 1.2.12Fixed in:1.2.12CVE-2026-27591derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.49%probability of exploitation in 30 days

39thpercentile

Low risk: more likely to be exploited than 39% of all known CVEs.

References

Patch1

github.com

Release Notes3

Related Vulnerabilities

Other CWE-284 (Improper Access Control) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-27350	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2019-1653	High	7.5	100%	KEV	-
CVE-2023-23752	Medium	5.3	100%	KEV	Fix
CVE-2023-38205	High	7.5	100%	KEV	-
CVE-2023-29298	High	7.5	100%	KEV	-
CVE-2024-27348	Critical	9.8	99%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-19.