CVE-2026-50281 | Craft CMS: Mass assignment via id in newAttributes during bulk duplicate overwrites existing elements

Craft CMS is a content management system (CMS). Versions 5.7.0 and above, prior to 5.9.21 contain a mass-assignment flaw in the bulk-duplicate element action. An attacker who is only able to duplicate their own entires can submit an arbitrary id through the newAttributes request parameter. The duplication routine overrides its own id = null reset with that value and writes the attacker's attributes into the victim's existing entry row. ElementsController::beforeAction() pulls the request body into $this->_attributes and rejects requests that ship an id or canonicalId key at the top level, actionBulkDuplicate(), reads a separate newAttributes array and passes it straight through to the service layer. Elements::duplicateElement() clones the source element, sets id to null, and then hands the attacker's array to Craft::configure(), which overwrites the reset id with any numeric value inside $newAttributes. PHP Yii's saveElement() then performs an UPDATE against the row with that primary key instead of an INSERT. The attackers's title, slug, authorId, postDate, and UID land on the victim's entry. safeAttributes() on Entry includes id because the base element model exposes it, so the Collection::only() filter does not strip it. This issue has been fixed in version 5.9.21.

Published: 2026-07-02 Last update: 2026-07-02 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-50281 is rated Low Risk (34.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.25%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-50281

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-03 — 0.25% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-50281

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 4.0 HIGH
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]

Weakness enumeration for CVE-2026-50281

GitHub Security Advisory for CVE-2026-50281

GHSA-x5m4-g2cq-52pq · Severity: high · Ecosystem: composer — Craft CMS's mass assignment via id in newAttributes during bulk duplicate overwrites existing elements

Affected software / configurations for CVE-2026-50281

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-50281

cvelogic Threat Intelligence