libnbd-release-notes-1.20(1) LIBNBD libnbd-release-notes-1.20(1)

# [NAME](#NAME)

libnbd-release-notes-1.20 - release notes for libnbd 1.20

# [DESCRIPTION](#DESCRIPTION)

These are the release notes for libnbd stable release 1.20. This describes the major changes since 1.18.

libnbd 1.20.0 was released on **5 April 2024**.

## [Security](#Security)

Fuzzing found and Eric Blake fixed an assertion which could be triggered by connecting to a malicious server. This was assigned CVE-2023-5871 (low severity). See the announcement here: https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/5CRC7LRTN35WPZZ4BT6NAMH4JGMF47IK/

If you find a security issue, please read *SECURITY* in the source (online here: https://gitlab.com/nbdkit/libnbd/blob/master/SECURITY). To find out about previous security issues in libnbd, see [**libnbd-security**(3)](/man/os/libnbd/libnbd-security.3).

## [Enhancements to existing APIs](#Enhancements_to_existing_APIs)

[**nbd\_connect\_uri**(3)](/man/os/libnbd/nbd_connect_uri.3) now correctly supports case insensitive URIs.

## [Protocol](#Protocol)

Improve interop with [**nbd-server**(1)](/man/os/libnbd/nbd-server.1) which supports structured replies but not meta context (Eric Blake).

## [Tools](#Tools)

[**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1) adds support for *--isnt*, *--cannot*, *--hasnt*, which lets you check if features of an NBD server are *not* supported.

[**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1) adds support for *--uri* which just prints the canonical URI of the server.

[**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1) now prints human sizes for block size constraints (Eric Blake).

## [Language bindings](#Language_bindings)

New [**libnbd-rust**(3)](/man/os/libnbd/libnbd-rust.3) manual page added, providing an overview for writing Rust programs using libnbd.

Rust documentation has been improved by using a custom translator from our own documentation format (Perl POD) to rustdoc.

Some Rust compiler warnings were fixed (Eric Blake).

OCaml bindings now support zero-copy in AIO pread and pwrite functions. This change is backwards compatible with existing code. (Thanks Nicolas Ojeda Bar, Anil Madhavapeddy, Simon Cruanes).

OCaml bindings now use "Gc.finalize" (OCaml-level finalizers instead of C-level finalizers) which improves compatibility in OCaml 5.1.1 and above (Guillaume Munch-Maccagnoni).

OCaml ≥ 4.05 is formally required and checked in *./configure*. Previously we did not specify a minimum version of OCaml, but in practice versions older than 4.05 probably didn't work.

## [Tests](#Tests)

Fuzzing approach was changed to use asynchronous commands. This improves speed of fuzzing greatly and should find more issues.

Multiple CI fixes (Eric Blake).

Respect the user's choice of qemu-nbd, nbdkit and other binaries from (eg) "./configure NBDKIT=/some/nbdkit". Previously we would often test against binaries found on the path even if the user had specified other binaries to use.

## [Other improvements and bug fixes](#Other_improvements_and_bug_fixes)

[**nbdinfo**(1)](/man/os/libnbd/nbdinfo.1) now gracefully disconnects from the server in error cases, improving output (Eric Blake).

"struct nbd\_handle" now contains a magic value which is checked on entry to libnbd, which should identify mistakes where programs calling libnbd pass in an incorrect pointer.

## [Documentation](#Documentation)

An example was added of how to use userfaultfd to mmap an NBD-backed drive. See *examples/userfault-map.c* in the libnbd sources.

Documentation of acceptable handle states in the man pages has been improved.

## [Build](#Build)

*contrib/libnbd.m4* is a contributed configure test for libnbd (Bruno Haible).

"./configure --with-bash-completions" will now fail if the required bash-completions package is not installed.

# [SEE ALSO](#SEE_ALSO)

[**libnbd**(3)](/man/os/libnbd/libnbd.3).

# [AUTHORS](#AUTHORS)

[Eric Blake](#Eric)

[Richard W.M. Jones](#Richard)

[Thomas Weißschuh](#Thomas)

# [COPYRIGHT](#COPYRIGHT)

Copyright Red Hat

# [LICENSE](#LICENSE)

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

2026-10-11 libnbd-1.25.7

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Document: libnbd-release-notes-1.20(1) from libnbd 1.25.7-r3 (Chainguard OS)