CVE-2026-28781

Q: How do I fix CVE-2026-28781?

Upgrade craft cms to 5.9.0 or later.

Q: Is CVE-2026-28781 being actively exploited?

Not that we know of. CVE-2026-28781 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.33% is the estimated probability that it will be exploited in the next 30 days. That is higher than 25% of all scored CVEs.

Q: How severe is CVE-2026-28781?

CVE-2026-28781 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-28781 affect?

Published advisories record a fix for craft cms (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

MEDIUM

6.5

CVSS v3

NVD

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.

CWE-639Authorization Bypass Through User-Controlled Key CWE-915

How to fix

Remediation Available

craft cmsNVD

Affected:>= 5.0.0, < 5.9.0Fixed in:5.9.0CVE-2026-28781derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.33%probability of exploitation in 30 days

25thpercentile

Low risk: more likely to be exploited than 25% of all known CVEs.

References

Patch3

Related Vulnerabilities

Other CWE-639 (Authorization Bypass Through User-Controlled Key) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-6875	Critical	9.8	90%	-	-
CVE-2024-46982	High	7.5	59%	-	Fix
CVE-2021-45428	Critical	9.8	57%	-	-
CVE-2019-17382	Critical	9.1	54%	-	Fix
CVE-2026-55255	High	8.4	29%	KEV	Fix
CVE-2019-13360	Critical	9.8	24%	-	-

Common questions

How do I fix CVE-2026-28781?

Upgrade craft cms to 5.9.0 or later.

Is CVE-2026-28781 being actively exploited?

Not that we know of. CVE-2026-28781 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.33% is the estimated probability that it will be exploited in the next 30 days. That is higher than 25% of all scored CVEs.

How severe is CVE-2026-28781?

CVE-2026-28781 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-28781 affect?

Published advisories record a fix for craft cms (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-05.