CVE-2026-34989: CI4MS: Profile & User Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.4%, percentile 38: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 38% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes ci4-cms-erp/ci4ms (Composer (PHP)) <= 0.28.6.0, fixed in 31.0.0.0. Check your lockfile, including transitive dependencies.

What it is

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to 31.0.0.0, the application fails to properly sanitize user-controlled input when users update their profile name (e.g., full name / username). An attacker can inject a malicious JavaScript payload into their profile name, which is then stored server-side. This stored payload is later rendered unsafely in multiple application views without proper output encoding, leading to stored cross-site scripting (XSS). This vulnerability is fixed in 31.0.0.0.

From the GitHub advisory

Summary Vulnerability 1: Stored DOM XSS via Profile Name Update (Persistent Payload Injection) - Stored Cross-Site Scripting via Unsanitized User Name in Profile Management

Description The application fails to properly sanitize user-controlled input when users update their profile name (e.g., full name / username). An attacker can inject a malicious JavaScript payload into their profile name, which is then stored server-side.

This stored payload is later rendered unsafely in multiple application views without proper output encoding, leading to stored cross-site scripting (XSS).

Affected Functionality - Profile name / full name update functionality (both the 2 user inputs) - User profile storage and retrieval logic

Attack Scenario - An attacker updates their profile name to include a malicious XSS payload. - The application stores this value without sanitization or encoding. - The payload persists and executes whenever the name is rendered in affected views.

Weakness type: CWE-79, CWE-269.

Product: ci4-cms-erp/ci4ms (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-04-06

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: low (any account)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.45% probability of exploitation activity in the next 30 days; percentile 38.

Timeline

• 2026-04-03 — GitHub-reviewed advisory GHSA-vr2g-rhm5-q4jr published (critical)
• 2026-04-06 — CVE record published by GitHub_M
• 2026-04-07 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-vr2g-rhm5-q4jr github.com
2. CVE.org record CVE-2026-34989 cve.org
3. NVD entry CVE-2026-34989 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

Critical Composer (PHP) advisories · Today’s Security Digest