VulnerabilityPublished 21 Jun 2026Updated 23 Jun 2026

CVE-2026-56381: craftcms cms · Cross-site Scripting

Affects craftcms cmsSource CVE Database V5

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Not known to be exploited · CVSS 4.6 Medium : upgrade to 5.8.22 when convenient.

Data as of 3 Nov 2026, 22:58 UTC

CVSS 4.0 base score

4.6Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.8.22

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: High
User Interaction: Active
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: High: The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
User Interaction: Active: Successful exploitation of this vulnerability requires a targeted user to perform specific, conscious interactions with the vulnerable system and the attacker’s payload, or the user’s interactions would actively subvert protection mechanisms which would lead to exploitation of the vulnerability.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade craftcms cms to 5.8.22.

Affected software

Product	Affected	Fixed in
craftcmscms	Affected >=5.0.0-RC1 <5.8.22	Fixed in 5.8.22
GitHubcraftcms/cms`pkg:github/craftcms/cms`Other threats	Affected =5.0.0-RC1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, restrict admin access to trusted users only and avoid using user group names containing untrusted input.

Description

## Summary A stored XSS vulnerability exists in the User Permissions page. The User Group name is rendered without proper HTML escaping in the permissions section, allowing an attacker to execute arbitrary JavaScript when another user views or edits a user's permissions. > [!NOTE] > This is a separate vulnerability from the previously reported "[Stored XSS via User Group Name in User Settings Page](https://github.com/craftcms/cms/security/advisories/GHSA-2423-8xxj-wc3g)" and "[Multiple Stored XSS in User Group Edit Page](https://github.com/craftcms/cms/security/advisories/GHSA-vx7g-xw92-g4xj)". This affects a different sink: the individual user's permissions page. ## Proof of Concept ### Required Permissions - Admin access - `allowAdminChanges` is enabled in production, which is against our [security recommendations](https://craftcms.com/knowledge-base/securing-craft). ### Steps to Reproduce 1. Log in to the control panel as an admin 2. Navigate to **Settings → Users → User Groups** 3. Create or edit a user group and set the **Name** field to: ```html <img src=x onerror="alert('XSS')" hidden> ``` 4. Save the user group 5. Navigate to **Users** and edit any user (`/admin/users/{id}`) 6. Click on the **Permissions** tab 7. XSS executes ## Mitigation Sanitize user group names when rendering in the user permissions template. ## References https://github.com/craftcms/cms-ghsa-4mgv-366x-qxvx/pull/2

Impact

An attacker with admin privileges can inject arbitrary JavaScript code that executes in the browsers of other users who view or edit user permissions. This can lead to unauthorized actions performed on behalf of those users or theft of session information. The vulnerability requires high privileges (admin access) and user interaction (viewing/editing permissions). The overall impact is limited by these conditions but still poses a risk of cross-site scripting attacks within the administrative interface.

Summary

CVE-2026-56381 is a stored cross-site scripting vulnerability in Craft CMS 5.0.0-RC1. The issue occurs on the User Permissions page where user group names are not properly HTML-escaped before rendering. An attacker with administrative privileges can inject JavaScript code via the user group name field. This code executes in the context of other users who access the permissions page, potentially leading to script execution within their browsers. The vulnerability has a CVSS 4.6 (medium) score and no known exploits in the wild.

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What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Jun 2026, 21:49 UTC

Technical details

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