CVE-2020-16135

libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.

libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.

Security Fix(es):

• libssh: NULL pointer dereference in sftpserver.c if ssh_buffer_new returns NULL (CVE-2020-16135)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.5 Release Notes linked from the References section.

libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.

Security Fix(es):

• libssh: NULL pointer dereference in sftpserver.c if ssh_buffer_new returns NULL (CVE-2020-16135)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

The code in src/sftpserver.c did not verify the validity of certain pointers and expected them to be valid. A NULL pointer dereference could have been occurred that typically causes a crash and thus a denial-of-service (CVE-2020-16135).

Integer overflow due to missing input sanitation in rdpegfx channel. The input rectangles from the server are not checked against local surface coordinates and blindly accepted. A malicious server can send data that will crash the client later on (invalid length arguments to a memcpy) (CVE-2020-15103).

The freerdp package has been updated to version 2.2.0, fixing this issue and other bugs.

These are all security issues fixed in the libssh-config-0.9.6-1.2 package on the GA media of openSUSE Tumbleweed.

This update for libssh fixes the following issues:

Update to version 0.9.8 (jsc#PED-7719):

• Fix CVE-2023-6004: Command injection using proxycommand (bsc#1218209)
• Fix CVE-2023-48795: Potential downgrade attack using strict kex (bsc#1218126)
• Fix CVE-2023-6918: Missing checks for return values of MD functions (bsc#1218186)
• Allow @ in usernames when parsing from URI composes

Update to version 0.9.7:

• Fix CVE-2023-1667: a NULL dereference during rekeying with algorithm guessing (bsc#1211188)
• Fix CVE-2023-2283: a possible authorization bypass in pki_verify_data_signature under low-memory conditions (bsc#1211190)
• Fix several memory leaks in GSSAPI handling code

Update to version 0.9.6 (bsc#1189608, CVE-2021-3634):

• https://git.libssh.org/projects/libssh.git/tag/?h=libssh-0.9.6

Update to 0.9.5 (bsc#1174713, CVE-2020-16135):

• CVE-2020-16135: Avoid null pointer dereference in sftpserver (T232)
• Improve handling of library initialization (T222)
• Fix parsing of subsecond times in SFTP (T219)
• Make the documentation reproducible
• Remove deprecated API usage in OpenSSL
• Fix regression of ssh_channel_poll_timeout() returning SSH_AGAIN
• Define version in one place (T226)
• Prevent invalid free when using different C runtimes than OpenSSL (T229)
• Compatibility improvements to testsuite

Update to version 0.9.4

• https://www.libssh.org/2020/04/09/libssh-0-9-4-and-libssh-0-8-9-security-release/
• Fix possible Denial of Service attack when using AES-CTR-ciphers CVE-2020-1730 (bsc#1168699)

Update to version 0.9.3

• Fixed CVE-2019-14889 - SCP: Unsanitized location leads to command execution (bsc#1158095)
• SSH-01-003 Client: Missing NULL check leads to crash in erroneous state
• SSH-01-006 General: Various unchecked Null-derefs cause DOS
• SSH-01-007 PKI Gcrypt: Potential UAF/double free with RSA pubkeys
• SSH-01-010 SSH: Deprecated hash function in fingerprinting
• SSH-01-013 Conf-Parsing: Recursive wildcards in hostnames lead to DOS
• SSH-01-014 Conf-Parsing: Integer underflow leads to OOB array access
• SSH-01-001 State Machine: Initial machine states should be set explicitly
• SSH-01-002 Kex: Differently bound macros used to iterate same array
• SSH-01-005 Code-Quality: Integer sign confusion during assignments
• SSH-01-008 SCP: Protocol Injection via unescaped File Names
• SSH-01-009 SSH: Update documentation which RFCs are implemented
• SSH-01-012 PKI: Information leak via uninitialized stack buffer

Update to version 0.9.2

• Fixed libssh-config.cmake
• Fixed issues with rsa algorithm negotiation (T191)
• Fixed detection of OpenSSL ed25519 support (T197)

Update to version 0.9.1

• Added support for Ed25519 via OpenSSL
• Added support for X25519 via OpenSSL
• Added support for localuser in Match keyword
• Fixed Match keyword to be case sensitive
• Fixed compilation with LibreSSL
• Fixed error report of channel open (T75)
• Fixed sftp documentation (T137)
• Fixed known_hosts parsing (T156)
• Fixed build issue with MinGW (T157)
• Fixed build with gcc 9 (T164)
• Fixed deprecation issues (T165)
• Fixed known_hosts directory creation (T166)

• Split out configuration to separate package to not mess up the library packaging and coinstallation

Update to verion 0.9.0

• Added support for AES-GCM
• Added improved rekeying support
• Added performance improvements
• Disabled blowfish support by default
• Fixed several ssh config parsing issues
• Added support for DH Group Exchange KEX
• Added support for Encrypt-then-MAC mode
• Added support for parsing server side configuration file
• Added support for ECDSA/Ed25519 certificates
• Added FIPS 140-2 compatibility
• Improved known_hosts parsing
• Improved documentation
• Improved OpenSSL API usage for KEX, DH, and signatures

• Add libssh client and server config files

This update for libssh fixes the following issues:

Update to version 0.9.8 (jsc#PED-7719):

• Fix CVE-2023-6004: Command injection using proxycommand (bsc#1218209)
• Fix CVE-2023-48795: Potential downgrade attack using strict kex (bsc#1218126)
• Fix CVE-2023-6918: Missing checks for return values of MD functions (bsc#1218186)
• Allow @ in usernames when parsing from URI composes

Update to version 0.9.7

• Fix CVE-2023-1667: a NULL dereference during rekeying with algorithm guessing (bsc#1211188)
• Fix CVE-2023-2283: a possible authorization bypass in pki_verify_data_signature under low-memory conditions (bsc#1211190)
• Fix several memory leaks in GSSAPI handling code

Update to version 0.9.6 (bsc#1189608, CVE-2021-3634)

• https://git.libssh.org/projects/libssh.git/tag/?h=libssh-0.9.6

Update to version 0.9.5 (bsc#1174713, CVE-2020-16135):

• CVE-2020-16135: Avoid null pointer dereference in sftpserver (T232)
• Improve handling of library initialization (T222)
• Fix parsing of subsecond times in SFTP (T219)
• Make the documentation reproducible
• Remove deprecated API usage in OpenSSL
• Fix regression of ssh_channel_poll_timeout() returning SSH_AGAIN
• Define version in one place (T226)
• Prevent invalid free when using different C runtimes than OpenSSL (T229)
• Compatibility improvements to testsuite

Update to version 0.9.4:

• https://www.libssh.org/2020/04/09/libssh-0-9-4-and-libssh-0-8-9-security-release/
• Fix possible Denial of Service attack when using AES-CTR-ciphers CVE-2020-1730 (bsc#1168699)

Update to version 0.9.3:

• Fixed CVE-2019-14889 - SCP: Unsanitized location leads to command execution (bsc#1158095)
• SSH-01-003 Client: Missing NULL check leads to crash in erroneous state
• SSH-01-006 General: Various unchecked Null-derefs cause DOS
• SSH-01-007 PKI Gcrypt: Potential UAF/double free with RSA pubkeys
• SSH-01-010 SSH: Deprecated hash function in fingerprinting
• SSH-01-013 Conf-Parsing: Recursive wildcards in hostnames lead to DOS
• SSH-01-014 Conf-Parsing: Integer underflow leads to OOB array access
• SSH-01-001 State Machine: Initial machine states should be set explicitly
• SSH-01-002 Kex: Differently bound macros used to iterate same array
• SSH-01-005 Code-Quality: Integer sign confusion during assignments
• SSH-01-008 SCP: Protocol Injection via unescaped File Names
• SSH-01-009 SSH: Update documentation which RFCs are implemented
• SSH-01-012 PKI: Information leak via uninitialized stack buffer

Update to version 0.9.2:

• Fixed libssh-config.cmake
• Fixed issues with rsa algorithm negotiation (T191)
• Fixed detection of OpenSSL ed25519 support (T197)

Update to version 0.9.1:

• Added support for Ed25519 via OpenSSL
• Added support for X25519 via OpenSSL
• Added support for localuser in Match keyword
• Fixed Match keyword to be case sensitive
• Fixed compilation with LibreSSL
• Fixed error report of channel open (T75)
• Fixed sftp documentation (T137)
• Fixed known_hosts parsing (T156)
• Fixed build issue with MinGW (T157)
• Fixed build with gcc 9 (T164)
• Fixed deprecation issues (T165)
• Fixed known_hosts directory creation (T166)

Update to verion 0.9.0:

• Added support for AES-GCM
• Added improved rekeying support
• Added performance improvements
• Disabled blowfish support by default
• Fixed several ssh config parsing issues
• Added support for DH Group Exchange KEX
• Added support for Encrypt-then-MAC mode
• Added support for parsing server side configuration file
• Added support for ECDSA/Ed25519 certificates
• Added FIPS 140-2 compatibility
• Improved known_hosts parsing
• Improved documentation
• Improved OpenSSL API usage for KEX, DH, and signatures

• Add libssh client and server config files

It was discovered that libssh incorrectly handled certain requests. An attacker could possibly use this issue to cause a denial of service.