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NVD / CVE Program· CNA GitHub_M

CVE-2026-40099: Kirby's page creation API bypasses the changeStatus permission check via unfiltered isDraft parameter

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: getkirby/cms (Packagist) 5.4.0, 4.9.0.

Low priority for now. Upgrade to getkirby/cms (Packagist) 5.4.0, 4.9.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Kirby is an open-source content management system. Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions. For pages, Kirby provides the `pages.create` and `pages.changeStatus` permissions (among others). Prior to versions 4.9.0 and 5.4.0, Kirby checked these permissions independently and only for the respective action. However the `changeStatus` permission didn't take effect on page creation. New pages are created as drafts by default and need to be published by changing the page status of an existing page draft. This is ensured when the page is created via the Kirby Panel. However the REST API allows to override the `isDraft` flag when creating a new page. This allowed authenticated attackers with the `pages.create` permission to immediately create published pages, bypassing the normal editorial workflow. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. Kirby has added a check to the page creation rules that ensures that users without the `pages.changeStatus` permission cannot create published pages, only page drafts.

MediumCVSS 5.3 · v4.0—No exploit Fix available
Published
Apr 24, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 19th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-40099

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
getkirbykirby

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • getkirby kirbybefore 4.9.0
  • getkirby kirby5.0.0 and later · before 5.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • getkirby kirby

    • < 4.9.0, >= 5.0.0, < 5.4.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistgetkirby/cmsfrom 5.0.0 · before 5.4.05.4.0
Packagistgetkirby/cmsbefore 4.9.04.9.0

Same product

getkirby: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-38490Kirby XML External Entity (XXE) vulnerability in the XML data handler
    41Plan
  • CVE-2026-44177Kirby: Pre-authentication path traversal and PHP file inclusion during user lookup
    36Monitor
  • CVE-2026-54003Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-32870Apr 24, 2026 · Kirby has XML injection in its XML creator toolkit
    27Monitor
  • ← EarlierCVE-2026-34587Apr 24, 2026 · Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering
    30Monitor
  • Later →CVE-2026-41325Apr 24, 2026 · Kirby is vulnerable to authorization bypass during page, file and user creation via blueprint injection
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Packagist:getkirby/cms4.9.0Package registry (OSV)
Packagist:getkirby/cms5.4.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-413250 days apartKirby is vulnerable to authorization bypass during page, file and user creation via blueprint injection
    28Monitor
  • CVE-2026-21896106 days apartKirby is missing permission checks in the content changes API
    23Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records