AIKIDO-2026-10288
zlib is vulnerable to Buffer Overflow
80
High Risk
This Affects:
zlibTL;DR
Affected versions of the zlib gem are vulnerable to a buffer overflow in Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes to an existing output buffer but does not ensure that the underlying Ruby string has sufficient capacity before shifting existing data with memmove. This can lead to a buffer overflow and memory corruption when the buffer length exceeds its allocated capacity.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
zlib is vulnerable to Buffer Overflow in versions 0.0.1 - 3.0.0, 3.1.0 - 3.1.1 and 3.2.0 - 3.2.2.
How to fix this
Upgrade the zlib library to the patch version.
Links
GitHub Release
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SOC 2Compliant
ISO 27001Compliant