CVE-2026-13723

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 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS

0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-25)

CWEs

CWE-22, CWE-59

Published

2026-07-29

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

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

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