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NVD / CVE Program· CNA GitHub_M

CVE-2026-71415: Kirby: File upload permissions are not checked during processing of chunk data

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.42% (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 kirby 5.5.2.

Low priority for now. Upgrade to getkirby kirby 5.5.2 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. From 5.0.0 until 5.5.2, Kirby's REST API chunk upload handler in src/Api/Upload.php did not run the relevant upload authorization preflight in Kirby\Api\Upload::process() before Kirby\Api\Upload::processChunk() persisted chunk data. An authenticated user with the access.panel permission enabled but with files.create, files.replace, and user/users.update permissions disabled could submit requests with an Upload-Length header and leave unfinished chunks in site/cache/.uploads for 24 hours. Repeating this process could consume attacker-controlled temporary storage, prevent other users from uploading files, or prevent site logic from storing data, although final permission checks still prevented unauthorized files from reaching the content or site/accounts directories. This issue is fixed in version 5.5.2.

HighCVSS 7.1 · v4.0—No exploit Fix available
Published
Aug 31, 2026
Updated
Sep 8, 2026
EPSS
0.4% · 37th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.1
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:N/VA:H/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.

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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.

—

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

    • >= 5.0.0, < 5.5.2affected

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 5.5.25.5.2

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-2026-45368Jul 16, 2026 · Kirby: Cross-site scripting (XSS) from links in KirbyTags and image blocks in the site frontend
    33Monitor
  • ← EarlierCVE-2026-69127Aug 7, 2026 · Kirby: System path exposure from error messages in the REST API
    27Monitor
  • Later →CVE-2026-75592Aug 31, 2026 · Kirby: Access to image files outside of the site root via path traversal in the media handling
    27Monitor

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
getkirby kirby5.5.2 · descriptionVendor (CNA)
Packagist:getkirby/cms5.5.2Package 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.

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-2026-5400553 days apartKirby: `pages.access` permission is not checked in the `site/find` REST API route
    28Monitor
  • CVE-2026-42069114 days apartKirby: Read access to site, user and role information is not gated by permissions
    28Monitor
  • CVE-2026-42137114 days apartKirby: `pages.access/list` and `files.access/list` permissions are not consistently checked in the REST API and changes dialog
    28Monitor
  • CVE-2026-5400453 days apartKirby: Access to files of top-level drafts is not protected by permissions
    25Monitor
  • CVE-2026-4417646 days apartKirby: `pages.access` permission is not checked during rendering of page drafts
    24Monitor
  • CVE-2026-4533446 days apartKirby: Content locks disclose IDs and emails of inaccessible users from `users.access/list` permissions
    21Monitor

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

CVSS vector

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

Change log

  1. Fix✗ → ✓

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References

All records