Threat Intelligence Database

adm-zip is a JavaScript library for creating and extracting ZIP archives in Node.js. Prior to 0.6.1, adm-zip applies the Unix permission bits stored in a zip entry directly to the extracted file via `fs.chmodSync()` when `keepOriginalPermission=true` is passed to `extractAllTo()`/`extractEntryTo()` — and it never filters the setuid/setgid/sticky bits out of those bits. A zip crafted by an attacker can therefore produce an extracted binary with mode `04755`. When extraction runs as root (the default posture in Docker builds, CI runners, and privileged install steps — the exact environments where this flag is used), the resulting root-owned setuid file is executed later by a lesser-privileged user, turning the attacker's code into a root execution. Version 0.6.1 fixes the issue.

A vulnerability in adm-zip version 0.6.0 allows bypassing decompression-bomb protection by setting the declared uncompressed size in a ZIP entry to zero. This causes the decompression output size limit to be ignored, potentially leading to excessive memory allocation and process crashes. The issue arises because the decompression cap is only applied when the declared size is greater than zero. A patch is available to address this flaw.

adm-zip is a JavaScript library for creating and extracting ZIP archives in Node.js. Prior to 0.6.1, getData() in zipEntry.js trusts an entry's central-directory uncompressed size and allocates output memory before validating that value against the actual compressed data and decompression result. A small crafted ZIP can declare a multi-gigabyte uncompressed size, causing Buffer.alloc and decompression handling to commit excessive resident memory before CRC validation reports an error. Applications that read entries from untrusted archives can therefore be terminated by the operating system or suffer service-wide memory exhaustion. This issue is fixed in version 0.6.1.

adm-zip versions 0.5.14 through 0.6.0 fail to apply zlib decompression output limits when ZIP entries declare zero uncompressed size. Attackers can craft malicious ZIP archives with highly compressible entries declaring zero size to exhaust memory and cause denial of service.

CVE-2026-76845 is a vulnerability in cthackers adm-zip versions 0.5.9 through 0.6.0 where symbolic links are followed during archive extraction, allowing an attacker to write files outside the intended extraction directory. This occurs because the sanitization only compares string paths without properly preventing symbolic link traversal, and the extraction functions open files without safeguards against link following. An attacker who can place a symbolic link inside a shared or predictable extraction directory can cause arbitrary file overwrite if the extracting process has write permissions and overwrite is enabled.

adm-zip before 0.5.18 is vulnerable to denial of service via a crafted ZIP file with a manipulated uncompressed size header field. In zipEntry.js line 103, Buffer.alloc(_centralHeader.size) allocates memory based on the declared uncompressed size from the ZIP central directory header without validating it against the actual compressed data size or imposing any upper bound. The size value is read directly from the binary header at entryHeader.js line 266 with no bounds check. An attacker can craft a ~120-byte ZIP file that declares ~4GB uncompressed size, causing a memory allocation amplification ratio of over 33 million to 1. The allocation occurs before CRC validation, so the malicious payload cannot be rejected early. All extraction and read methods are affected: readFile(), readAsText(), extractEntryTo(), extractAllTo(), extractAllToAsync(), test(), and entry.getData(). Any application accepting untrusted ZIP files via adm-zip is vulnerable to immediate process crash.