Red Hat Security Advisory: postgresql:12 security update

Important

A flaw was found in PostgreSQL. An integer overflow in multiple server features allows an unprivileged database user to cause an undersized memory allocation that leads to an out-of-bounds write. This issue allows an attacker to execute arbitrary code as the operating system user running the database or, in applications that pass gigabyte-scale user inputs to the relevant database functions, to cause a segmentation fault, resulting in a denial of service.

CWE-190 - Integer Overflow or Wraparound

A flaw was found in PostgreSQL. This vulnerability, related to symlink following in pg_basebackup (plain format) and pg_rewind, allows an origin superuser to overwrite local files. By exploiting this, an attacker could potentially hijack the operating system account. This attack has practical implications if specific actions are taken, such as moving files to a different virtual machine (VM) or snapshotting the VM, between the execution of these commands and the server's restart.

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

A flaw was found in PostgreSQL libpq. A server superuser can exploit a buffer overflow vulnerability in the PQfn function, which is used by client functions such as lo_export(), lo_read(), lo_lseek64(), and lo_tell64(). This allows the superuser to send an arbitrarily large response, overwriting the client's stack memory, specifically in tools like psql and pg_dump. This could lead to arbitrary code execution on the client system.

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

A flaw was found in PostgreSQL. This vulnerability, a covert timing channel, exists in the comparison of MD5-hashed passwords during authentication. A remote attacker could exploit this to recover user credentials, gaining unauthorized access to the database. This issue specifically impacts databases that retain MD5-hashed passwords from upgrades of PostgreSQL 13 or earlier.

CWE-385 - Covert Timing Channel

A flaw was found in PostgreSQL. A stack buffer overflow in the 'refint' module allows an unprivileged database user to execute arbitrary code as the operating system user running the database. Additionally, a separate vulnerability exists where, if an application uses a user-controlled column as a 'refint' cascade primary key and allows user-controlled updates, a SQL injection can enable an attacker to execute arbitrary SQL commands as the database user performing the update.

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')