CVE-2026-34587

HIGHNVD 8.18.1
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, 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). In affected releases, 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 updated the Options logic to no longer double-resolve queries in option values coming from OptionsQuery or OptionsApi sources. Kirby now only resolves queries that are directly configured in the blueprints.

CVSS v3
8.1
EG Score
8.1(medium)
EPSS
25.4%
KEV
Not listed

Published

April 24, 2026

Last Modified

April 27, 2026

Advisory Details (3)

Auto-updated May 6, 2026
Patch available. Sources: github.
github Patch Available

Server-Side Template Injection (SSTI) via double template resolution in option rendering · Advisory · getkirby/kirby · GitHub

https://github.com/getkirby/kirby/security/advisories/GHSA-jcjw-58rv-c452
generic

Release 5.4.0 · getkirby/kirby · GitHub

https://github.com/getkirby/kirby/releases/tag/5.4.0
generic

Release 4.9.0 · getkirby/kirby · GitHub

https://github.com/getkirby/kirby/releases/tag/4.9.0

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
getkirby/cms5.0.0 ... 5.3.3 (21 versions)5.4.0

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Frequently asked(5)

What is CVE-2026-34587?
CVE-2026-34587 is a high vulnerability published on April 24, 2026. Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, 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/...).…
When was CVE-2026-34587 disclosed?
CVE-2026-34587 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on April 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-34587 actively exploited?
CVE-2026-34587 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-34587?
CVE-2026-34587 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-34587?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34587, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-34587

Explore →

Is Your Infrastructure Affected by CVE-2026-34587?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.