What’s Vulnerable › Vulnerabilities

CVE-2026-54003: Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header

• Severity: critical (CVSS 9.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-09 · updated 2026-10-25
• Weakness: CWE-454

Description

Kirby is an open-source content management system. Prior to 4.9.4 and from 5.4.4, Kirby sites with no configured user accounts that run on publicly accessible servers behind a reverse proxy setting the Forwarded, X-Client-IP, or X-Real-IP request header could allow remote attackers to install the Panel and create the first admin user because local-IP checks trusted those headers incorrectly. This issue is fixed in versions 4.9.4 and 5.4.4.

Affected products

• getkirby kirby: before 4.9.4; from 5.0.0, < 5.4.4

References

• https://github.com/getkirby/kirby/commit/1c7fee90e49153cf9ca4a6ec17481d25fbedc48d
• https://github.com/getkirby/kirby/commit/3423f66c01dbc0455862e23ee699d2aa469f3234
• https://github.com/getkirby/kirby/commit/66a3a14bf0892d320723ba766cd5f1d33a51d15b
• https://github.com/getkirby/kirby/commit/ab992dc149610b90e337c2955ab6ccb7f72ffb3a
• https://github.com/getkirby/kirby/pull/8166
• https://github.com/getkirby/kirby/releases/tag/4.9.4
• https://github.com/getkirby/kirby/releases/tag/5.4.4
• https://github.com/getkirby/kirby/security/advisories/GHSA-whxw-24jc-cwmv

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