= 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.">

NVD - CVE-2026-25541 (original) (raw)

CVE-2026-25541 Detail

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.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST CVSS score

NIST: NVD

N/A

NVD assessment not yet provided.

Nist CVSS score does not match with CNA score

CNA: GitHub, Inc.

CVSS-BT 5.5 MEDIUM

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

CVSS 3.x Severity and Vector Strings:

NIST CVSS score

NIST: NVD

Base Score: 7.5 HIGH

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/tokio-rs/bytes/commit/d0293b0e35838123c51ca5dfdf468ecafee4398f GitHub, Inc. Patch
https://github.com/tokio-rs/bytes/releases/tag/v1.11.1 GitHub, Inc. Product Release Notes
https://github.com/tokio-rs/bytes/security/advisories/GHSA-434x-w66g-qw3r GitHub, Inc. Exploit Vendor Advisory
https://rustsec.org/advisories/RUSTSEC-2026-0007.html GitHub, Inc. Exploit Third Party Advisory

Weakness Enumeration

CWE-ID CWE Name Source
CWE-680 Integer Overflow to Buffer Overflow GitHub, Inc.

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Initial Analysis by NIST 2/27/2026 3:13:28 PM

Action Type Old Value New Value
Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Added CPE Configuration OR *cpe:2.3:a:tokio-rs:bytes:*:*:*:*:*:rust:*:* versions from (including) 1.2.1 up to (excluding) 1.11.1
Added Reference Type GitHub, Inc.: https://github.com/tokio-rs/bytes/commit/d0293b0e35838123c51ca5dfdf468ecafee4398f Types: Patch
Added Reference Type GitHub, Inc.: https://github.com/tokio-rs/bytes/releases/tag/v1.11.1 Types: Product, Release Notes
Added Reference Type GitHub, Inc.: https://github.com/tokio-rs/bytes/security/advisories/GHSA-434x-w66g-qw3r Types: Exploit, Vendor Advisory
Added Reference Type GitHub, Inc.: https://rustsec.org/advisories/RUSTSEC-2026-0007.html Types: Exploit, Third Party Advisory

New CVE Received from GitHub, Inc. 2/04/2026 5:16:00 PM

Action Type Old Value New Value
Added 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.
Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Added CWE CWE-680
Added Reference https://github.com/tokio-rs/bytes/commit/d0293b0e35838123c51ca5dfdf468ecafee4398f
Added Reference https://github.com/tokio-rs/bytes/releases/tag/v1.11.1
Added Reference https://github.com/tokio-rs/bytes/security/advisories/GHSA-434x-w66g-qw3r
Added Reference https://rustsec.org/advisories/RUSTSEC-2026-0007.html

Quick Info

CVE Dictionary Entry:
CVE-2026-25541
NVD Published Date:
02/04/2026
NVD Last Modified:
02/27/2026
Source:
GitHub, Inc.