decompress-zip CVE-2026-107709

Exploitation requires that a target application (or user) use decompress-zip version ≤0.3.3 to extract an attacker-controlled ZIP archive - the attacker must get the crafted archive into the extraction workflow (upload, download, or supplied package). The vulnerability triggers during extraction when crafted entry paths resolve to prefix-sibling directories, so a writable sibling path outside the intended extraction directory must exist for the overwrite to land on something useful. Limiting factors: the CVSS vector is local (AV:L) with required user/application interaction (UI:R) and no network exposure, so there is no remote unauthenticated trigger; escalation to full RCE is conditional on the environment containing a sibling file whose overwrite yields code execution. No special authentication is needed (PR:N), but a victim must initiate the extraction.

Signals are mixed and point to a real-but-conditional risk rather than an urgent mass-exploitation threat. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R, 7.8 HIGH) is explicitly LOCAL with required user interaction - this is a Zip Slip-class flaw triggered when an application or user extracts an attacker-supplied archive, NOT a remotely reachable unauthenticated service. The 'RCE' tag and the description's 'remote code execution' language are conditional ('depending on the target environment and writable sibling paths') and should not be read as network-exploitable: the attack vector remains local/UI-dependent. No EPSS score was provided (exploitation-probability unknown), the CVE is NOT in CISA KEV (no confirmed active exploitation), and no POC=YES flag was supplied - however a technical write-up describing the 'sibling-prefix bypass' is referenced (moizxsec.github.io), which materially lowers the barrier to developing working exploit code even though finished exploit code is not confirmed. SSVC-style read: exploitation = none confirmed; automatable = partial (crafting the archive is trivial and scriptable, but delivery depends on a victim extracting it); technical impact = total (file overwrite escalating to code execution). Net: a legitimately dangerous library bug worth prioritizing in dependency remediation, but not a drop-everything internet-facing emergency - the local vector and user-interaction requirement cap real-world urgency.

An attacker crafts a malicious ZIP whose entry names resolve to a prefix-sibling directory (e.g. escaping the intended extraction folder) and delivers it to an application that uses decompress-zip ≤0.3.3 to unpack uploaded or downloaded archives. When the archive is extracted, files are written outside the target directory, overwriting a sensitive file (startup script, config, or a module the app later loads), which can lead to application compromise or code execution. A public technical write-up detailing the sibling-prefix bypass exists, lowering the effort to reproduce the attack, though no packaged exploit is confirmed.