Fwd: libtasn1-4.21.0 released [stable] - fixes CVE-2025-13151

[Alan Coopersmith <alan.coopersmith () oracle com>]

CVE-2025-13151 is described in the CVE database as:

  Stack-based buffer overflow in libtasn1 version: v4.20.0.
  The function fails to validate the size of input data resulting
  in a buffer overflow in asn1_expend_octet_string.


-------- Forwarded Message --------
Subject: libtasn1-4.21.0 released [stable]
Date: Thu, 08 Jan 2026 14:48:27 +0100
From: Simon Josefsson via Announcements and Requests for Help from the GNU project and the Free Software Foundation 
<info-gnu () gnu org>
Reply-To: Simon Josefsson <simon () josefsson org>
To: info-gnu () gnu org
CC: help-libtasn1 () gnu org

This is to announce libtasn1-4.21.0, a stable release.

GNU Libtasn1 is a standalone library written in C for manipulating
ASN.1 objects including DER/BER encoding/decoding.  GNU Libtasn1 is
used by GnuTLS to handle X.509 structures.

There have been 34 commits by 5 people in the 49 weeks since 4.20.0.

See the NEWS below for a brief summary.

Thanks to everyone who has contributed!
The following people contributed changes to this release:

  Andrew Hamilton (1)
  Daiki Ueno (4)
  Masatake YAMATO (1)
  Simon Josefsson (27)
  Vijay Sarvepalli (1)

Happy Hacking,
/Simon [on behalf of the libtasn1 maintainers]
==================================================================

Here is the GNU libtasn1 home page:
    https://www.gnu.org/software/libtasn1/

Here are the compressed sources and a GPG detached signature:
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-4.21.0.tar.gz
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-4.21.0.tar.gz.sig

Here is minimal source-only "git archive" sources:
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-v4.21.0-src.tar.gz
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-v4.21.0-src.tar.gz.sig

Here are Sigsum Proofs:
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-4.21.0.tar.gz.proof
  https://ftp.gnu.org/gnu/libtasn1/libtasn1-v4.21.0-src.tar.gz.proof

Use a mirror for higher download bandwidth:
  https://www.gnu.org/order/ftp.html

Here are the SHA256 and SHA3-256 checksums:

  SHA256 (libtasn1-4.21.0.tar.gz) = HYpESiI8xUZCQHdzRuEl3lHY5qvwuLrHQqyEYJFn3Ic=
  SHA3-256 (libtasn1-4.21.0.tar.gz) = XtNk+w/VLnMrJZlT3CZQy/Mgwm/cmWTdX6ZBb49ETwk=

  SHA256 (libtasn1-v4.21.0-src.tar.gz) = BvfQ93s42ztrF6PVTVkIdOXlib6oCBMpqKOs++w9/iE=
  SHA3-256 (libtasn1-v4.21.0-src.tar.gz) = l6gEY3JXjHxWYVIPk8F8H6P6qWWdUbVmZPvGRewQnsU=

Verify the base64 SHA256 checksum with cksum -a sha256 --check
from coreutils-9.2 or OpenBSD's cksum since 2007.

Verify the base64 SHA3-256 checksum with cksum -a sha3 --check
from coreutils-9.8.

Use a .sig file to verify that the corresponding file (without the
.sig suffix) is intact.  First, be sure to download both the .sig file
and the corresponding tarball.  Then, run a command like this:

  gpg --verify libtasn1-4.21.0.tar.gz.sig

The signature should match the fingerprint of the following key:

  pub   ed25519 2019-03-20 [SC]
        B1D2 BD13 75BE CB78 4CF4  F8C4 D73C F638 C53C 06BE
  uid   Simon Josefsson <simon () josefsson org>

If that command fails because you don't have the required public key,
or that public key has expired, try the following commands to retrieve
or refresh it, and then rerun the 'gpg --verify' command.

  gpg --locate-external-key simon () josefsson org

  gpg --recv-keys 51722B08FE4745A2

  wget -q -O- 'https://savannah.gnu.org/project/release-gpgkeys.php?group=libtasn1&download=1&apos; | gpg --import -

As a last resort to find the key, you can try the official GNU
keyring:

  wget -q https://ftp.gnu.org/gnu/gnu-keyring.gpg
  gpg --keyring gnu-keyring.gpg --verify libtasn1-4.21.0.tar.gz.sig

Use the .proof files to verify the Sigsum proof.  These files are like
signatures but with extra transparency: you can cryptographically verify
that every signature is logged in a public append-only log, so you can
say with confidence what signatures exists.  This makes hidden releases
no longer deniable for the same public key.

Releases are Sigsum-signed with the following public key:

  cat <<EOF > libtasn1-sigsum-key.pub
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILzCFcHHrKzVSPDDarZPYqn89H5TPaxwcORgRg+4DagE
EOF

Run a command like this to verify downloaded artifacts:

  sigsum-verify -k libtasn1-sigsum-key.pub -P sigsum-generic-2025-1 \
        libtasn1-4.21.0.tar.gz.proof < libtasn1-4.21.0.tar.gz

You may learn more about Sigsum concepts and find instructions how to
download the tools here: https://www.sigsum.org/getting-started/

This release is based on the libtasn1 git repository, available as

  git clone https://codeberg.org/libtasn1/libtasn1.git

with commit 83f96d790a8107889e7c570294d49227b2db9d61 tagged as v4.21.0.

For a summary of changes and contributors, see:

  https://codeberg.org/libtasn1/libtasn1/commits/tag/v4.21.0

or run this command from a git-cloned libtasn1 directory:

  git shortlog v4.20.0..v4.21.0

This release was bootstrapped with the following tools:
  Gnulib 2026-01-01 e93789db7e86c51d6cb9683ea508e676a55cdefa
  Autoconf 2.72
  Automake 1.17
  Libtoolize 2.4.7
  Make 4.4.1
  Makeinfo 7.1.1
  Bison 3.8.2
  Help2man 1.49.2
  Gtkdocize 1.34.0
  Tar 1.35
  Gzip 1.13
  Guix ac92638bcec817cbbf94201eab0b342553987d42

NEWS.md

# Noteworthy changes in release 4.21.0 (2026-01-08) [stable]
- Undocumented asn1Decoding --debug flag removed, thanks to Andrew Hamilton.
- Code coverage for src/ went from 35% to 82%, thanks to Andrew Hamilton.
- Fix of ASN.1 typo in manual, thanks to Masatake YAMATO.
- NEWS renamed to NEWS.md and uses markdown syntax.
- Update gnulib files and various build/maintenance fixes.
- Fix for vulnerability CVE-2025-13151 Stack-based buffer overflow