Vulnerability Description
A vulnerability in the `zipx.Unzip` extraction routine of Develar's app-builder allows an attacker to overwrite arbitrary files on macOS APFS by exploiting a Unicode Normalization Collision combined with symlink following behavior. APFS treats certain Unicode equivalent filenames as identical (e.g., ß ↔ ss), while app builder performs no canonical normalization before validating or writing paths. As a result, a crafted ZIP archive containing: • a symlink entry named ss pointing to a target file, and • a regular file named ß containing attacker controlled data, will cause the second write to follow the symlink and overwrite the target file.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- http://kb.cert.org/vuls/id/293714
- https://github.com/develar/app-builder
- https://github.com/develar/app-builder/pull/163
- https://www.kb.cert.org/vuls/id/293714
FAQ
What is CVE-2026-13723?
CVE-2026-13723 is a vulnerability with a CVSS score of 6.5 (MEDIUM). A vulnerability in the `zipx.Unzip` extraction routine of Develar's app-builder allows an attacker to overwrite arbitrary files on macOS APFS by exploiting a Unicode Normalization Collision combined w...
How severe is CVE-2026-13723?
CVE-2026-13723 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-13723?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.