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Debian LTS Advisory DLA-3559-1                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                       Guilhem Moulin
September 08, 2023                            https://wiki.debian.org/LTS
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Package        : libssh2
Version        : 1.8.0-2.1+deb10u1
CVE ID         : CVE-2019-13115 CVE-2019-17498 CVE-2020-22218
Debian Bug     : 932329 943562

Vulnerabilities were found in libssh2, a client-side C library
implementing the SSH2 protocol, which could lead to denial of service or
remote information disclosure.

CVE-2019-13115

    Kevin Backhouse discovered an integer overflow vulnerability in kex.c's
    kex_method_diffie_hellman_group_exchange_sha256_key_exchange()
    function, which could lead to an out-of-bounds read in the way
    packets are read from the server.  A remote attacker who compromises
    an SSH server may be able to disclose sensitive information or cause
    a denial of service condition on the client system when a user
    connects to the server.

CVE-2019-17498

    Kevin Backhouse discovered that the SSH_MSG_DISCONNECT logic in
    packet.c has an integer overflow in a bounds check, thereby enabling
    an attacker to specify an arbitrary (out-of-bounds) offset for a
    subsequent memory read.  A malicious SSH server may be able to
    disclose sensitive information or cause a denial of service
    condition on the client system when a user connects to the server.

CVE-2020-22218

    An issue was discovered in function _libssh2_packet_add(), which
    could allow attackers to access out of bounds memory.

For Debian 10 buster, these problems have been fixed in version
1.8.0-2.1+deb10u1.

We recommend that you upgrade your libssh2 packages.

For the detailed security status of libssh2 please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/libssh2

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