CVE-2026-25541

Name of the Vulnerable Software and Affected Versions Bytes versions 1.2.1 through 1.11.0

Description The Bytes library contains a flaw in the BytesMut::reserve function that can lead to an integer overflow. Specifically, an unchecked addition within the reclaim path of BytesMut::reserve can cause the allocated capacity to be incorrectly calculated when new cap + offset overflows a usize value in release builds. This can result in the cap value being set to a value exceeding the actual allocated capacity. Subsequent calls to functions like spare capacity mut() may then create out-of-bounds slices, leading to undefined behavior. This issue is observable in release builds, while debug builds trigger a panic due to overflow checks.

Recommendations Update to Bytes version 1.11.1 or later.