Amazon Linux 2023 : postgresql18, postgresql18-contrib, postgresql18-llvmjit (ALAS2023-2026-1780)

high Nessus Plugin ID 319870

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1780 advisory.

Missing authorization in PostgreSQL CREATE TYPE allows an object creator to hijack other queries that use search_path to find user-defined types, including extension-defined types. That is to say, the victim will execute arbitrary SQL functions of the attacker's choice. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6472)

Integer wraparound in multiple PostgreSQL server features allows an unprivileged database user to cause the server to undersize an allocation and write out-of-bounds. This may execute arbitrary code as the operating system user running the database. In applications that pass gigabyte-scale user inputs to the relevant database functions, the application input provider may achieve a segmentation fault. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6473)

Externally-controlled format string in PostgreSQL timeofday() function allows an attacker to retrieve portions of server memory, via crafted timezone zones. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6474)

Symlink following in PostgreSQL pg_basebackup plain format and in pg_rewind allows an origin superuser to overwrite local files, e.g. /var/lib/postgres/.bashrc, that hijack the operating system account. It will remain the case that starting the server after these commands implicitly trusts the origin superuser, due to features like shared_preload_libraries. Hence, the attack has practical implications only if one takes relevant action between these commands and server start, like moving the files to a different VM or snapshotting the VM. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.
(CVE-2026-6475)

SQL injection in PostgreSQL pg_createsubscriber allows an attacker with pg_create_subscription rights to execute arbitrary SQL as a superuser. The attack takes effect when pg_createsubscriber next runs. Within major versions 17 and 18, minor versions before PostgreSQL 18.4 and 17.10 are affected. Versions before PostgreSQL 17 are unaffected. (CVE-2026-6476)

Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary- length, server-determined data into a buffer of unspecified size. Because both the \lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory.
Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6477)

Covert timing channel in comparison of MD5-hashed password in PostgreSQL authentication allows an attacker to recover user credentials sufficient to authenticate. This does not affect scram-sha-256 passwords, the default in all supported releases. However, current databases may have MD5-hashed passwords originating in upgrades from PostgreSQL 13 or earlier. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6478)

Uncontrolled recursion in PostgreSQL SSL and GSS negotiation allows an attacker able to connect to a PostgreSQL AF_UNIX socket to achieve sustained denial of service. If SSL and GSS are both disabled, an attacker can do the same via access to a PostgreSQL TCP socket. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6479)

Buffer over-read in PostgreSQL function pg_restore_attribute_stats() accepts array values of unmatched length, which causes query planning to read past end of one array. This allows a table maintainer to infer memory values past that array end. Within major version 18, minor versions before PostgreSQL 18.4 are affected. Versions before PostgreSQL 18 are unaffected. (CVE-2026-6575)

Stack buffer overflow in PostgreSQL module refint allows an unprivileged database user to execute arbitrary code as the operating system user running the database. A distinct attack is possible if the application declares a user-controlled column as a refint cascade primary key and facilitates user- controlled updates to that column. In that case, a SQL injection allows a primary key update value provider to execute arbitrary SQL as the database user performing the primary key update. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. (CVE-2026-6637)

SQL injection in PostgreSQL logical replication ALTER SUBSCRIPTION ... REFRESH PUBLICATION allows a subscriber table creator to execute arbitrary SQL with the subscription's publication-side credentials.
The attack takes effect at the next REFRESH PUBLICATION. Within major versions 16, 17, and 18, minor versions before PostgreSQL 18.4, 17.10, and 16.14 are affected. Versions before PostgreSQL 16 are unaffected. (CVE-2026-6638)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'dnf update postgresql18 --releasever 2023.12.20260608' or or 'dnf update --advisory ALAS2023-2026-1780 --releasever 2023.12.20260608' to update your system.

Plugin Details

Severity: High

ID: 319870

File Name: al2023_ALAS2023-2026-1780.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 6/8/2026

Updated: 6/8/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 6.7

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-6638

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:postgresql18-private-libs-debuginfo, p-cpe:/a:amazon:linux:postgresql18-llvmjit, p-cpe:/a:amazon:linux:postgresql18-upgrade-devel, p-cpe:/a:amazon:linux:postgresql18-private-libs, p-cpe:/a:amazon:linux:postgresql18, p-cpe:/a:amazon:linux:postgresql18-test, p-cpe:/a:amazon:linux:postgresql18-test-debuginfo, p-cpe:/a:amazon:linux:postgresql18-debuginfo, p-cpe:/a:amazon:linux:postgresql18-server, p-cpe:/a:amazon:linux:postgresql18-debugsource, p-cpe:/a:amazon:linux:postgresql18-plpython3, p-cpe:/a:amazon:linux:postgresql18-static, p-cpe:/a:amazon:linux:postgresql18-server-devel, p-cpe:/a:amazon:linux:postgresql18-docs, p-cpe:/a:amazon:linux:postgresql18-test-rpm-macros, p-cpe:/a:amazon:linux:postgresql18-private-devel, p-cpe:/a:amazon:linux:postgresql18-docs-debuginfo, p-cpe:/a:amazon:linux:postgresql18-plperl, p-cpe:/a:amazon:linux:postgresql18-server-devel-debuginfo, p-cpe:/a:amazon:linux:postgresql18-plperl-debuginfo, p-cpe:/a:amazon:linux:postgresql18-llvmjit-debuginfo, p-cpe:/a:amazon:linux:postgresql18-server-debuginfo, p-cpe:/a:amazon:linux:postgresql18-upgrade-devel-debuginfo, p-cpe:/a:amazon:linux:postgresql18-upgrade-debuginfo, p-cpe:/a:amazon:linux:postgresql18-contrib, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:postgresql18-pltcl, p-cpe:/a:amazon:linux:postgresql18-pltcl-debuginfo, p-cpe:/a:amazon:linux:postgresql18-contrib-debuginfo, p-cpe:/a:amazon:linux:postgresql18-upgrade, p-cpe:/a:amazon:linux:postgresql18-plpython3-debuginfo

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 6/8/2026

Vulnerability Publication Date: 5/14/2026

Reference Information

CVE: CVE-2026-6472, CVE-2026-6473, CVE-2026-6474, CVE-2026-6475, CVE-2026-6476, CVE-2026-6477, CVE-2026-6478, CVE-2026-6479, CVE-2026-6575, CVE-2026-6637, CVE-2026-6638

IAVB: 2026-B-0129

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