Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🐘 Packagist

GHSA-pgpf-m8m4-6cg6

CRITICAL

Winter vulnerable to privilege escalation by authenticated backend users

Also known asCVE-2026-27591
Published
Mar 12, 2026
Updated
Mar 14, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk38th percentile+0.38%
0.00%0.33%0.66%0.99%0.1%0.1%0.1%0.5%Apr 26Jun 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

3 pkgs affected
🐘winter/wn-backend-module🐘winter/wn-backend-module🐘winter/wn-backend-module

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Affected versions of 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.

The Winter CMS maintainers strongly recommend that all Winter CMS sites that have any reliance on the roles & permissions system to update immediately. Security fixes have been backported to all major versions of Winter (1.0, 1.1, and 1.2).

Patches

Multiple fixes and defence in depth has been applied to prevent current and future privilege escalation attacks at the lowest level possible.

This security issue has been fixed as of https://wintercms.com/releases/v1.0.477, https://wintercms.com/releases/v1.1.12, https://wintercms.com/releases/v1.2.12.

Workarounds

If you cannot upgrade, you may apply the changes from the releases to your Winter CMS installation manually to resolve this issue.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistwinter/wn-backend-module1.2.0&&< 1.2.121.2.12
🐘Packagistwinter/wn-backend-module1.1.0&&< 1.1.121.1.12
🐘Packagistwinter/wn-backend-moduleall versions1.0.477

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for winter/wn-backend-module. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update winter/wn-backend-module to 1.2.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pgpf-m8m4-6cg6 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-pgpf-m8m4-6cg6 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-pgpf-m8m4-6cg6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Impact Affected versions of 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. The Winter CMS maintainers strongly recommend that all Winter CMS sites that have any reliance on the roles & permissions system to update immediately. Security fixes have been backported to all major
O3 Security · Impact-Aware SCA

Is GHSA-pgpf-m8m4-6cg6 in your dependencies?

O3 detects GHSA-pgpf-m8m4-6cg6 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.