VulnerabilityPublished 4 Mar 2026

CVE-2026-28781: craftcms cms · Insecure Direct Object Reference

Affects craftcms cmsSource CVE Database V5

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Not known to be exploited · CVSS 7.1 High : upgrade to 5.9.0-beta.1 or 4.17.0-beta.1 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score

7.1High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.9.0-beta.1, 4.17.0-beta.1

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
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: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable 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 4 Mar 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 30 Oct 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 5.9.0-beta.1 or 4.17.0-beta.1.

Affected software

Product	Affected	Fixed in
craftcmscms	Affected >=5.0.0-RC1 <5.9.0-beta.1	Fixed in 5.9.0-beta.1
craftcmscms	Affected >=4.0.0-RC1 <4.17.0-beta.1	Fixed in 4.17.0-beta.1
GitHubcraftcms/cms`pkg:github/craftcms/cms`Other threats	Affected =4.17.0-beta.1 =5.9.0-beta.1	Fixed in–

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

AI-suggested

Organizations should upgrade Craft CMS installations to version 4.17.0-beta.1 or later, or 5.9.0-beta.1 or later, where the vulnerability is fixed. Until upgrades can be applied, administrators should audit user permissions and restrict the 'Create Entries' permission to trusted users only, minimizing the attack surface. Implementing web application firewalls (WAFs) with custom rules to detect and block POST requests containing unauthorized 'authorId' or 'authorIds[]' parameters can provide temporary protection. Monitoring CMS logs for unusual author assignment patterns or unexpected content authorship changes can help detect exploitation attempts. Additionally, organizations should review content approval workflows to include verification of authorship changes and consider multi-factor authentication for administrative accounts to reduce risk from spoofed authorship. Regular security assessments and penetration testing focusing on CMS authorization controls are recommended to identify similar weaknesses.

Description

Craft is a content management system (CMS). Prior to 4.17.0-beta.1 and 5.9.0-beta.1, the entry creation process allows for Mass Assignment of the authorId attribute. A user with "Create Entries" permission can inject the authorIds[] (or authorId) parameter into the POST request, which the backend processes without verifying if the current user is authorized to assign authorship to others. Normally, this field is not present in the request for users without the necessary permissions. By manually adding this parameter, an attacker can attribute the new entry to any user, including Admins. This effectively "spoofs" the authorship. This vulnerability is fixed in 4.17.0-beta.1 and 5.9.0-beta.1.

Impact

This vulnerability can have significant impacts on organizations using affected versions of Craft CMS. By allowing unauthorized assignment of authorship, attackers can spoof content ownership, potentially misleading internal audits, content approval workflows, and accountability mechanisms. This can facilitate further social engineering or privilege escalation attempts if attackers attribute malicious content to trusted administrators. It may also disrupt content management processes and damage organizational reputation if unauthorized or malicious content appears to originate from privileged users. Although the vulnerability does not directly allow privilege escalation or data exfiltration, the integrity impact is high, as it undermines trust in content provenance. Organizations relying on Craft CMS for public-facing websites or internal portals may face reputational damage or operational disruption. The ease of exploitation and network accessibility increase the risk of widespread abuse, especially in environments where many users have 'Create Entries' permissions. No known exploits in the wild reduce immediate risk, but the vulnerability should be treated as urgent due to its potential misuse.

CWE-639Authorization Bypass Through User-Controlled Key (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #24OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
Architecture and Design
For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
Architecture and Design · Implementation
Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
Architecture and Design
Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
OWASP Cheat Sheets
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
Insecure Direct Object Reference Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V4.1.2 (opens in a new tab)
V4.2.1 (opens in a new tab)
V8.3.8 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-915Improperly Controlled Modification of Dynamically-Determined Object Attributes (opens in a new tab)
Base weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.
Implementation
If available, use features of the language or framework that allow specification of allowlists of attributes or fields that are allowed to be modified. If possible, prefer allowlists over denylists.
Architecture and Design · Implementation
If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
Implementation · Input Validation
For any externally-influenced input, check the input against an allowlist of internal object attributes or fields that are allowed to be modified.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
Software Supply Chain Security (opens in a new tab)
Infrastructure as Code (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 17:02 UTC

WeaknessesCWE-639, CWE-915

Technical details

References

Community reviews

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