Buffer Overflow Affecting ruby package, versions <3.4.9-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

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  • Snyk IDSNYK-ALPINE323-RUBY-15690958
  • published19 Mar 2026
  • disclosed16 Apr 2026

Introduced: 19 Mar 2026

NewCVE-2026-27820  (opens in a new tab)
CWE-120  (opens in a new tab)
CWE-131  (opens in a new tab)

How to fix?

Upgrade Alpine:3.23 ruby to version 3.4.9-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ruby package and not the ruby package as distributed by Alpine. See How to fix? for Alpine:3.23 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1