CVE-2026-25541
HIGH
GHSA-434x-w66g-qw3r
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4Tags
Description
Bytes is a utility library for working with bytes. From version 1.2.1 to before 1.11.1, Bytes is vulnerable to integer overflow in BytesMut::reserve. In the unique reclaim path of BytesMut::reserve, if the condition "v_capacity >= new_cap + offset" uses an unchecked addition. When new_cap + offset overflows usize in release builds, this condition may incorrectly pass, causing self.cap to be set to a value that exceeds the actual allocated capacity. Subsequent APIs such as spare_capacity_mut() then trust this corrupted cap value and may create out-of-bounds slices, leading to UB. This behavior is observable in release builds (integer overflow wraps), whereas debug builds panic due to overflow checks. This issue has been patched in version 1.11.1.
Analysis
Integer overflow in the Bytes library versions 1.2.1 through 1.11.0 allows attackers to corrupt the BytesMut capacity value, leading to out-of-bounds memory access and undefined behavior in release builds. Public exploit code exists for this vulnerability, affecting applications that depend on Bytes for buffer management. …
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Remediation
Within 24 hours: Identify all internal and third-party applications using Bytes library versions 1.2.1 through 1.11.0 via dependency scanning tools and software bill of materials (SBOM) review. Within 7 days: Apply vendor patch to upgrade Bytes to version 1.11.1 or later across all affected systems, prioritizing production and customer-facing applications. …
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External POC / Exploit Code
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