CVE-2026-34558Public exploitNetwork attack vector

Account takeover via globally rendered stored XSS

Published Mar 30, 2026 · Updated Mar 30, 2026

Stored XSS in CI4MS before 0.31.0.0 allows remote authenticated users to take over accounts via crafted Methods Management fields. The module stores unsanitized field values and renders them without output encoding in administrative interfaces and global navigation. Any low-privilege role able to manage methods can plant a payload that executes across navigation views, exposing victim sessions to account takeover.

CVSS severity9.1
Critical
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in CI4MS before 0.31.0.0 allows remote authenticated users to take over accounts via crafted Methods Management fields. The module stores unsanitized field values and renders them without output encoding in administrative interfaces and global navigation. Any low-privilege role able to manage methods can plant a payload that executes across navigation views, exposing victim sessions to account takeover.

The record

CVE
CVE-2026-34558
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
Ci4MS
Product
CI4MS
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.31.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Ci4MS · CI4MSversion=< 0.31.0.0

Published CVSS scores

9.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
9.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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