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Zlib

3 CVEs product

Monthly

CVE-2026-27820 Ruby LOW PATCH GHSA Monitor

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 ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.

Buffer Overflow Zlib
NVD GitHub VulDB
CVSS 4.0
1.7
EPSS
0.0%
CVE-2026-27171 LOW POC Monitor

zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts within a loop that has no termination condition. [CVSS 2.9 LOW]

Information Disclosure Zlib
NVD GitHub
CVSS 3.1
2.9
EPSS
0.0%
CVE-2026-22184 HIGH PATCH This Week

Local privilege escalation in zlib 1.3.1.2 and earlier allows authenticated users to achieve arbitrary code execution through a buffer overflow in the contrib/untgz utility when processing command-line arguments with excessively long archive names. The vulnerability affects only the standalone untgz demonstration tool and does not impact the core zlib library. No patch is currently available.

Buffer Overflow Memory Corruption Zlib Red Hat Suse
NVD GitHub VulDB
CVSS 3.1
7.8
EPSS
0.0%
EPSS 0% CVSS 1.7
LOW PATCH Monitor

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 ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.

Buffer Overflow Zlib
NVD GitHub VulDB
EPSS 0% CVSS 2.9
LOW POC Monitor

zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts within a loop that has no termination condition. [CVSS 2.9 LOW]

Information Disclosure Zlib
NVD GitHub
EPSS 0% CVSS 7.8
HIGH PATCH This Week

Local privilege escalation in zlib 1.3.1.2 and earlier allows authenticated users to achieve arbitrary code execution through a buffer overflow in the contrib/untgz utility when processing command-line arguments with excessively long archive names. The vulnerability affects only the standalone untgz demonstration tool and does not impact the core zlib library. No patch is currently available.

Buffer Overflow Memory Corruption Zlib +2
NVD GitHub VulDB

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