CVE-2026-68743

A flaw was found in SSSD. The extract_authtok_v1() function in the PAM responder does not validate the auth_token_length field against the remaining buffer size before processing. A local attacker can exploit this via a crafted protocol v1 request to the PAM responder socket, causing an out-of-bounds read and process crash, resulting in a denial of service.

• CVE-2026-68743: validate auth_token_length in extract_authtok_v1() to prevent an out-of-bounds read from a crafted PAM protocol v1 request

• CVE-2026-68743: validate auth_token_length in the PAM responder protocol v1 handler to prevent an out-of-bounds read

• CVE-2026-68743: validate auth_token_length in the PAM responder protocol v1 handler to prevent an out-of-bounds read

• CVE-2026-68743: validate auth_token_length against the remaining request buffer in the PAM responder's extract_authtok_v1(), preventing an out-of-bounds read

• CVE-2026-68743: validate auth_token_length in extract_authtok_v1() to prevent an out-of-bounds read in the PAM responder

• CVE-2026-68743: validate auth_token_length in extract_authtok_v1() to prevent an out-of-bounds read in the PAM responder

This update for sssd fixes the following issues:

Security issues fixed:

• CVE-2026-68742: insufficient validation in the NSS responder can lead to an out-of-bounds read and a process crash when a crafted GETHOSTBYADDR request is sent to the NSS responder socket (bsc#1273922).
• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-68744: improper memory management in the NSS responder can lead to uninitialized heap memory disclosure from the sssd_nss process (bsc#1273924).

Other updates and bugfixes:

• Add systemd-tmpfiles configuration file to populate /var/lib/sss with the correct permissions on transactional servers (bsc#1274748).

This update for sssd fixes the following issues:

• CVE-2026-68742: insufficient validation in the NSS responder can lead to an out-of-bounds read and a process crash when a crafted GETHOSTBYADDR request is sent to the NSS responder socket (bsc#1273922).
• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-68744: improper memory management in the NSS responder can lead to uninitialized heap memory disclosure from the sssd_nss process (bsc#1273924).

This update for sssd fixes the following issues:

• CVE-2026-68742: insufficient validation in the NSS responder can lead to an out-of-bounds read and a process crash when a crafted GETHOSTBYADDR request is sent to the NSS responder socket (bsc#1273922).
• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-68744: improper memory management in the NSS responder can lead to uninitialized heap memory disclosure from the sssd_nss process (bsc#1273924).

This update for sssd fixes the following issues:

Security issues fixed:

• CVE-2026-68742: insufficient validation in the NSS responder can lead to an out-of-bounds read and a process crash when a crafted GETHOSTBYADDR request is sent to the NSS responder socket (bsc#1273922).
• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-68744: improper memory management in the NSS responder can lead to uninitialized heap memory disclosure from the sssd_nss process (bsc#1273924).

Other updates and bugfixes:

• Add systemd-tmpfiles configuration file to populate /var/lib/sss with the correct permissions on transactional servers (bsc#1274748).

This update for sssd fixes the following issues:

Security issues fixed:

• CVE-2026-68742: insufficient validation in the NSS responder can lead to an out-of-bounds read and a process crash when a crafted GETHOSTBYADDR request is sent to the NSS responder socket (bsc#1273922).
• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-68744: improper memory management in the NSS responder can lead to uninitialized heap memory disclosure from the sssd_nss process (bsc#1273924).

Other updates and bugfixes:

• Add systemd-tmpfiles configuration file to populate /var/lib/sss with the correct permissions on transactional servers (bsc#1274748).

This update for sssd fixes the following issue:

• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).

This update for sssd fixes the following issues:

• CVE-2026-68742: unvalidated address lengths in NSS responder packet parsing can cause a heap out-of-bounds read (bsc#1273922).
• CVE-2026-68743: oversized length parameters in authentication requests can cause heap out-of-bounds reads (bsc#1273925).
• CVE-2026-68744: unshrunk packet allocations during group resolution can allow uninitialized heap memory disclosure (bsc#1273924).

Changes for sssd:

• Warn about ldap_sudo_search_base only if sudo target is enabled; (bsc#1273009)

This update for sssd fixes the following issue:

• CVE-2026-68743: oversized length parameters in authentication requests can cause heap out-of-bounds reads (bsc#1273925).

This update for sssd fixes the following issues:

• CVE-2026-68743: insufficient validation in the PAM responder can lead to an out-of-bounds read and a process crash when a crafted protocol v1 request is processed (bsc#1273925).
• CVE-2026-12610: cancelled or completed PAM request while the asynchronous child process is still running can lead to a use-after-free (bsc#1269807).

This update for sssd fixes the following issues:

• CVE-2026-12610: cancelled or completed PAM request while the asynchronous child process is still running can lead to a use-after-free (bsc#1269807).
• CVE-2026-68742: unvalidated address lengths in NSS responder packet parsing can cause a heap out-of-bounds read (bsc#1273922).
• CVE-2026-68743: oversized length parameters in authentication requests can cause heap out-of-bounds reads (bsc#1273925).
• CVE-2026-68744: unshrunk packet allocations during group resolution can allow uninitialized heap memory disclosure (bsc#1273924).
• CVE-2026-90462: Fail-open in LDAP ppolicy access check allows continued authorization (bsc#1282584).
• CVE-2026-90463: out-of-bounds read in the NSS service request parsers (bsc#1280360).
• CVE-2026-90994: out-of-bounds read in PAM v1 parser (bsc#1280361).
• CVE-2026-90995: NULL pointer dereference in PAM responder (bsc#1280362).
• CVE-2026-90996: zero-length request body underflow in the NSS responder (bsc#1280363).
• CVE-2026-92821: access control bypass due to premature LDAP access rule evaluation (bsc#1284326).
• CVE-2026-104029: denial of service due to out-of-bounds read in autofs responder (bsc#1284314).
• CVE-2026-104031: denial of service via memory exhaustion in autofs responder (bsc#1284316).
• CVE-2026-104033: access control bypass due to improper LDAP shadow expiration check (bsc#1284318).
• CVE-2026-104036: denial of service due to out-of-bounds write in NFS idmap plugin (bsc#1284321).
• CVE-2026-104037: denial of service due to packet length underflow in autofs responder (bsc#1284322).
• CVE-2026-104038: denial of service via missing SID extension in certificate mapping (bsc#1284323).
• CVE-2026-104039: denial of service due to stale connection state reuse in PAM GSSAPI responder (bsc#1284324).
• CVE-2026-104043: Denial of Service via undersized packet parsing in NSS responder (bsc#1284266).
• CVE-2026-104045: denial of service via race condition in autofs responder (bsc#1284470).

It was discovered that SSSD did not properly validate authentication token lengths when processing PAM responder requests. A local attacker could possibly use this issue to cause SSSD to crash, resulting in a denial of service.