zlib vulnerabilities

1 known vulnerability in zlib from Ruby. 1 is rated high or critical. Each entry lists the affected versions and the release that fixes it, where the vendor has published one.

Latest first

• 9.8 Critical severity

  zlib: Buffer Copy without Checking Size of Input

  CVE-2026-27820Apr 16, 2026Ruby

  zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes