CVEvulnerability

CVE-2026-27820

1.7 LOW Published 2026-04-16 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-04-16
Last modified
2026-10-26
Assigner
[email protected]
CVSS 4.0 ([email protected])
1.7 LOW — CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-120, CWE-131

Description

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.

Affected configurations

• ruby-lang zlib (< 3.0.1) • ruby-lang zlib (>= 3.1.0 < 3.1.2) • ruby-lang zlib (>= 3.2.0 < 3.2.3)

Related

Weakness · CWE (2)

  • CWE-120 Buffer Copy without Checking Size of Input weakness
  • CWE-131 Incorrect Calculation of Buffer Size weakness

References