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Debian LTS Advisory DLA-3926-1                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                       Guilhem Moulin
October 21, 2024                              https://wiki.debian.org/LTS
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Package        : perl
Version        : 5.32.1-4+deb11u4
CVE ID         : CVE-2020-16156 CVE-2023-31484
Debian Bug     : 1015985 1035109

Vulnerabilities were found in Perl's CPAN.pm, which could lead CPAN
clients to install malicious modules.

CVE-2020-16156

    Stig Palmquist discovered that an attacker can prepend checksums for
    modified packages to the beginning of CHECKSUMS files, before the
    cleartext PGP headers, resulting in signature verification bypass.

    CPAN.pm has been updated so that when configured to validate the
    signature on CHECKSUMS, it will refuse to install a tarball if the
    associated CHECKSUMS file isn't signed.  The gpg(1) executable is
    required in order to validate signatures.

CVE-2023-31484

    Stig Palmquist discovered that CPAN::HTTP::Client did not verify
    X.509 certificates in the HTTP::Tiny call, which could allows an
    attacker to MITM the connection with the CPAN mirror.

    CPAN::HTTP::Client now enables the `verify_SSL` flag.  HTTPS mirrors
    therefore require a valid certificate.  The identity of the default
    mirror https://cpan.org can be verified after installing the
    'ca-certificates' package.

For Debian 11 bullseye, these problems have been fixed in version
5.32.1-4+deb11u4.

We recommend that you upgrade your perl packages.

For the detailed security status of perl please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/perl

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS