From: "nobu (Nobuyoshi Nakada) via ruby-core" Date: 2025-12-17T03:02:01+00:00 Subject: [ruby-core:124271] [Ruby Bug#21787] `IO::Buffer` Integer Overflow in Range Validation Leads to Out-of-Bounds Memory Access Issue #21787 has been updated by nobu (Nobuyoshi Nakada). Subject changed from `IO::Buffer` buffer overf to `IO::Buffer` Integer Overflow in Range Validation Leads to Out-of-Bounds Memory Access Backport changed from 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN to 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED From: https://hackerone.com/reports/3437743 The `IO::Buffer` implementation in Ruby contains a critical integer overflow vulnerability in its range validation logic. The `io_buffer_validate_range` function assumes that `offset+length` never wraps around, allowing an attacker to bypass bounds checking with a carefully chosen large offset value. When the sum overflows, it appears to be within bounds while the actual destination pointer underflows. Subsequent operations (write/read copies) use this wrapped offset without further validation, enabling out-of-bounds memory access directly from Ruby code. https://hackerone.com/reports/3437743#activity-38521790 > We decided to fix this as a regular bug since `IO::Buffer` is experimental. ---------------------------------------- Bug #21787: `IO::Buffer` Integer Overflow in Range Validation Leads to Out-of-Bounds Memory Access https://bugs.ruby-lang.org/issues/21787#change-115764 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Backport: 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED ---------------------------------------- -- https://bugs.ruby-lang.org/ ______________________________________________ ruby-core mailing list -- ruby-core@ml.ruby-lang.org To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org ruby-core info -- https://ml.ruby-lang.org/mailman3/lists/ruby-core.ml.ruby-lang.org/