What’s Vulnerable › Vulnerabilities

CVE-2023-41889: Late-Unicode normalization vulnerability in SHIRASAGI

• Severity: medium (CVSS 5.3 v3.1)
• 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: yes
• Published: 2023-09-15 · updated 2026-06-17
• Weakness: CWE-176

Description

SHIRASAGI is a Content Management System. Prior to version 1.18.0, SHIRASAGI is vulnerable to a Post-Unicode normalization issue. This happens when a logical validation or a security check is performed before a Unicode normalization. The Unicode character equivalent of a character would resurface after the normalization. The fix is initially performing the Unicode normalization and then strip for all whitespaces and then checking for a blank string. This issue has been fixed in version 1.18.0.

Affected products

• SHIRASAGI Project SHIRASAGI: before 1.18.0 — fixed in 1.18.0

How to fix

Upgrade to a fixed version: SHIRASAGI Project SHIRASAGI 1.18.0. Check the vendor advisory for mitigations.

References

• https://github.com/shirasagi/shirasagi/blob/f249ce3f06f6bfbc0017b38f5c13de424334c3ea/app/models/concerns/rdf/object.rb#L68-L72
• https://github.com/shirasagi/shirasagi/security/advisories/GHSA-xr45-c2jv-2v9r
• https://sim4n6.beehiiv.com/p/unicode-characters-bypass-security-checks
• https://github.com/shirasagi/shirasagi/blob/f249ce3f06f6bfbc0017b38f5c13de424334c3ea/app/models/concerns/rdf/object.rb#L68-L72
• https://github.com/shirasagi/shirasagi/security/advisories/GHSA-xr45-c2jv-2v9r
• https://sim4n6.beehiiv.com/p/unicode-characters-bypass-security-checks

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