Exploit discussion active in current signal (2 latest mentions)
Recommended action window: High priority (within 72h)
NVD 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.
Priority
LOW
Exploitation
NONE
PoC
YES
Patch
AVAILABLE
Momentum
NONE
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 … https://www.cve.org/CVERecord?id=CVE-2026-13723
Post summary
The text announces a Unicode-based file overwrite vulnerability in Develar's app-builder that affects macOS APFS.
Tomas Illuminati found a way to overwrite arbitrary files on macOS by feeding a specially crafted ZIP into Develar's app-builder - a transitive dependency of electron-builder used to package roughly every Electron app > CVE-2026-13723 exploits macOS APFS's Unicode normalization (ß ↔ ss) and unsafe symlink following in Develar's app-builder to write files outside the extraction directory > CERT/CC assigned CVE-2026-13723 and published the advisory on 2026-07-29 > CERT/CC disclosed a vulnerability in Develar's app-builder (used by electron-builder) that allows arbitrary file overwrite on macOS APFS via Unicode normalization > Electron-Userland responded quickly and shipped a mitigation for their users > an attacker can craft a ZIP archive that bypasses path validation, redirecting writes to any system file > supply-chain impact is broad; Electron-Userland has already mitigated, but the source package remains unpatched https://news.ojobit.com/story/apfs-unicode-collision-app-builder-electron-c6792b
Post summary
A new CVE (2026-13723) for macOS APFS has been disclosed with detailed exploit mechanics, and the Electron‑Userland community has released a mitigation.