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Update Rust crate bytes to v1.11.1 [SECURITY]#1532

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renovate/crate-bytes-vulnerability
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Update Rust crate bytes to v1.11.1 [SECURITY]#1532
renovate[bot] wants to merge 1 commit intomainfrom
renovate/crate-bytes-vulnerability

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@renovate renovate bot commented Feb 3, 2026

This PR contains the following updates:

Package Type Update Change
bytes dependencies patch 1.11.01.11.1

GitHub Vulnerability Alerts

CVE-2026-25541

Details

In the unique reclaim path of BytesMut::reserve, the condition

if 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.

PoC

use bytes::*;

fn main() {
    let mut a = BytesMut::from(&b"hello world"[..]);
    let mut b = a.split_off(5);

    // Ensure b becomes the unique owner of the backing storage
    drop(a);

    // Trigger overflow in new_cap + offset inside reserve
    b.reserve(usize::MAX - 6);

    // This call relies on the corrupted cap and may cause UB & HBO
    b.put_u8(b'h');
}

Workarounds

Users of BytesMut::reserve are only affected if integer overflow checks are configured to wrap. When integer overflow is configured to panic, this issue does not apply.

This vulnerability is also known as RUSTSEC-2026-0007.


Release Notes

tokio-rs/bytes (bytes)

v1.11.1

Compare Source

  • Fix integer overflow in BytesMut::reserve

Configuration

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@renovate renovate bot added the dependencies Pull requests that update a dependency file label Feb 3, 2026
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