How severe is CVE-2026-41891?

No CVSS score has been assigned to CVE-2026-41891 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-41891?

CVE-2026-41891 affects the following packages: ci4-cms-erp/ci4ms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-41891?

Update ci4-cms-erp/ci4ms to 0.31.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41891 is resolved across your whole dependency graph.

How do I detect CVE-2026-41891 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ci4-cms-erp/ci4ms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-41891 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-41891 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-41891 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-41891?

CVE-2026-41891 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 19th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-41891?

CVE-2026-41891 is classified as CWE-613 (CWE-613). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-41891 published, and has it been updated?

CVE-2026-41891 was published on May 7, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-41891 — ci4ms

Fix: ci4-cms-erp/ci4ms@2f38284

CVE-2026-41891 is a CWE-613 vulnerability in ci4-cms-erp/ci4ms. A fix is available for ci4-cms-erp/ci4ms — see the affected versions and patch details below.

CI4MS: Deactivated User Session Bypass (active=0)

Also known asGHSA-5hfv-c864-qcq9

Published

May 7, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41891.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs19th percentile — riskier than 19% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘ci4-cms-erp/ci4ms

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

Summary

The auth filter has the deactivated/banned user check commented out.

Details

CodeIgniter Shield's loggedIn() re-checks the status field (catching status='banned'), but does not re-check the active field for existing sessions. When an admin deactivates a user (active=0) after they have already logged in:

Their session cookie remains valid
auth()->loggedIn() still returns true
The commented-out code is the only mechanism that would have checked !$user->active

Evidence

Impact

User deactivation does NOT immediately revoke backend access
Deactivated user retains full access until session expires (default: 7200s)

Additional note

The commented-out block appears to be a deferred placeholder — it was written but disabled from the very first commit that introduced the filter, and has never been active. The later addition of SessionTracker (v0.31.4.0) suggests the dev was aware of the session revocation gap, but account-level deactivation (users.active = 0) remains unenforced. Could you verify if this is intentionally pending or simply forgotten and not documented?.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`ci4-cms-erp/ci4ms`	≥ 0.26.0&&< 0.31.8.0	0.31.8.0`composer require ci4-cms-erp/ci4ms:^0.31.8.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ci4-cms-erp/ci4ms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ci4-cms-erp/ci4ms to 0.31.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41891 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Summary The auth filter has the deactivated/banned user check commented out. ### Details CodeIgniter Shield's `loggedIn()` re-checks the `status` field (catching `status='banned'`), but does **not** re-check the `active` field for existing sessions. When an admin deactivates a user (`active=0`) after they have already logged in: - Their session cookie remains valid - `auth()->loggedIn()` still returns `true` - The commented-out code is the only mechanism that would have checked `!$user->active` ### Evidence <img width="981" height="654" alt="image" src="https://github.com/user-attachmen

O3 Security · Impact-Aware SCA

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