Kirby is an open-source content management system. From versions 5.0.0 to 5.2.1, Kirby is missing permission checks in the content changes API. This vulnerability affects all Kirby sites where user permissions are configured to prevent specific role(s) from performing write actions, specifically by disabling the update permission with the intent to prevent modifications to site content. This vulnerability does not affect those who have not altered the deviated from default user permissions. This issue has been patched in version 5.2.2.
CVE-2026-21896
This medium-severity CVE scores 5.7 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 91% 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).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.7
- EG Score
- 5.7(medium)
- EG Risk
- 26(Track)EG Risk 26/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity57% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 8.8%
- KEV
- Not listed
Published
January 8, 2026
Last Modified
February 2, 2026
References (3)
- security-advisories@githubhttps://github.com/getkirby/kirby/commit/f5ce1347b427b819bf193acf11fd0da232f7af47
- security-advisories@githubhttps://github.com/getkirby/kirby/releases/tag/5.2.2
- security-advisories@githubhttps://github.com/getkirby/kirby/security/advisories/GHSA-4j78-4xrm-cr2f
Affected Packages
(1 across 1 ecosystem)
Packagist(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| getkirby/cms | 5.0.0 ... 5.2.1 (14 versions) | 5.2.2 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 13× in last 7d / 46× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 03:06 UTCEG score recompute
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Related CVEs(same CWE)
Same CWE
10 shownCWE-863
Frequently asked(5)
What is CVE-2026-21896?
When was CVE-2026-21896 disclosed?
Is CVE-2026-21896 actively exploited?
What is the CVSS score of CVE-2026-21896?
How do I remediate CVE-2026-21896?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-21896
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