Vulnerability · Published Sep 18, 2026 · Assigned by GitHub_M

CVE-2026-77301adm-zip: Uncontrolled memory allocation via the declared uncompressed size (DoS)

High 7.5

In plain English

A high-severity security flaw in adm-zip from cthackers. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 50.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	adm-zip	0.6.1	GHSA-7q85-xj36-vmfc

Affected products (as reported)

Vendor	Product	Versions
cthackers	adm-zip	< 0.6.1

Weakness: CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/cthackers/adm-zip/security/advisories/GHSA-7q85-xj36-vmfc x_refsource_CONFIRM
https://github.com/cthackers/adm-zip/commit/491600683dacb6cb9fe0718a0eeb9cb5eb49afa6 x_refsource_MISC
https://github.com/cthackers/adm-zip/releases/tag/v0.6.1 x_refsource_MISC