CVE-2026-31859 Vulnerability Analysis & Exploit Details

CVE-2026-31859
Vulnerability Scoring

6.1
/10
High Risk

If left unpatched, CVE-2026-31859 could lead to major system disruptions or data loss.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-31859 Details

Status: Analyzed

Last updated: 🕑 17 Mar 2026, 14:03 UTC
Originally published on: 🕕 11 Mar 2026, 18:16 UTC

Time between publication and last update: 5 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVE-2026-31859 Vulnerability Summary

CVE-2026-31859: Craft is a content management system (CMS). The fix for CVE-2025-35939 in craftcms/cms introduced a strip_tags() call in src/web/User.php to sanitize return URLs before they are stored in the session. However, strip_tags() only removes HTML tags (angle brackets) -- it does not inspect or filter URL schemes. Payloads like javascript:alert(document.cookie) contain no HTML tags and pass through strip_tags() completely unmodified, enabling reflected XSS when the return URL is rendered in an href attribute. This vulnerability is fixed in 5.9.7 and 4.17.3.

Assessing the Risk of CVE-2026-31859

Access Complexity Graph

The exploitability of CVE-2026-31859 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-31859

With low attack complexity and no required privileges, CVE-2026-31859 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-31859, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-31859, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: Low
    CVE-2026-31859 could lead to minor leaks of non-critical information without major privacy breaches.
  • Integrity: Low
    Exploiting CVE-2026-31859 may cause minor changes to data without severely impacting its accuracy.
  • Availability: None
    CVE-2026-31859 does not impact system availability.

CVE-2026-31859 References

External References

CWE Common Weakness Enumeration

CWE-116

CAPEC Common Attack Pattern Enumeration and Classification

  • Cross Zone Scripting CAPEC-104 An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security.
  • User-Controlled Filename CAPEC-73 An attack of this type involves an adversary inserting malicious characters (such as a XSS redirection) into a filename, directly or indirectly that is then used by the target software to generate HTML text or other potentially executable content. Many websites rely on user-generated content and dynamically build resources like files, filenames, and URL links directly from user supplied data. In this attack pattern, the attacker uploads code that can execute in the client browser and/or redirect the client browser to a site that the attacker owns. All XSS attack payload variants can be used to pass and exploit these vulnerabilities.
  • Web Server Logs Tampering CAPEC-81 Web Logs Tampering attacks involve an attacker injecting, deleting or otherwise tampering with the contents of web logs typically for the purposes of masking other malicious behavior. Additionally, writing malicious data to log files may target jobs, filters, reports, and other agents that process the logs in an asynchronous attack pattern. This pattern of attack is similar to "Log Injection-Tampering-Forging" except that in this case, the attack is targeting the logs of the web server and not the application.
  • AJAX Footprinting CAPEC-85 This attack utilizes the frequent client-server roundtrips in Ajax conversation to scan a system. While Ajax does not open up new vulnerabilities per se, it does optimize them from an attacker point of view. A common first step for an attacker is to footprint the target environment to understand what attacks will work. Since footprinting relies on enumeration, the conversational pattern of rapid, multiple requests and responses that are typical in Ajax applications enable an attacker to look for many vulnerabilities, well-known ports, network locations and so on. The knowledge gained through Ajax fingerprinting can be used to support other attacks, such as XSS.

Vulnerable Configurations

  • cpe:2.3:a:craftcms:craft_cms:4.15.3:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.3:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.4:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.4:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.5:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.5:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.6:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.6:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.6.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.6.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.6.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.6.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.15.7:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.15.7:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.0:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.0:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.3:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.3:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.4:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.4:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.5:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.5:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.6:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.6:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.6.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.6.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.7:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.7:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.8:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.8:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.9:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.9:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.9.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.9.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.10:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.10:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.11:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.11:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.12:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.12:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.13:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.13:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.14:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.14:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.15:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.15:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.16:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.16:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.17:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.17:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.18:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.18:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.16.19:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.16.19:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.17.0:-:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.17.0:-:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.17.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.17.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.17.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.17.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.17.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.17.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:4.17.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:4.17.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.5:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.5:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.6:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.6:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.7:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.7:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.8:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.8:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.8.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.8.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.8.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.8.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.9:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.9:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.10:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.10:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.7.11:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.7.11:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.0:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.0:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.3:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.3:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.4:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.4:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.5:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.5:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.6:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.6:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.7:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.7:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.8:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.8:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.9:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.9:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.10:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.10:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.11:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.11:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.12:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.12:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.13:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.13:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.13.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.13.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.13.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.13.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.14:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.14:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.15:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.15:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.16:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.16:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.17:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.17:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.18:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.18:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.19:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.19:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.20:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.20:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.21:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.21:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.22:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.22:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.8.23:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.8.23:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.0:-:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.0:-:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.1:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.1:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.2:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.2:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.3:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.3:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.4:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.4:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.5:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.5:*:*:*:*:*:*:*
  • cpe:2.3:a:craftcms:craft_cms:5.9.6:*:*:*:*:*:*:*
    cpe:2.3:a:craftcms:craft_cms:5.9.6:*:*:*:*:*:*:*

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