RHEL 9 : osbuild-composer (RHSA-2026:62753)

high Nessus Plugin ID 342427

Synopsis

The remote Red Hat host is missing one or more security updates for osbuild-composer.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:62753 advisory.

A service for building customized OS artifacts, such as VM images and OSTree commits, that uses osbuild under the hood. Besides building images for local usage, it can also upload images directly to cloud. It is compatible with composer-cli and cockpit-composer clients.

Security Fix(es):

* net/mail: golang: net/mail: Denial of Service via pathological email address parsing (CVE-2026-42499)

* net/mail: golang: Go net/mail: Denial of Service via crafted email inputs (CVE-2026-39820)

* encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal (CVE-2026-33818)

* net/url: golang: golang net/url: Denial of Service from quadratic complexity in path resolution (CVE-2026-56860)

* net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service (CVE-2026-56853)

* html/template: golang: Go html/template: Cross-Site Scripting via pathological input (CVE-2026-56858)

* crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages (CVE-2026-56862)

* encoding/xml: golang: Go: Denial of Service via XML decoding recursion depth issue (CVE-2026-56859)

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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux 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

Update the RHEL osbuild-composer package based on the guidance in RHSA-2026:62753.

Plugin Details

Severity: High

ID: 342427

File Name: redhat-RHSA-2026-62753.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 9/2/2026

Updated: 9/2/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.51

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-39820

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:redhat:rhel_e4s:9.4, p-cpe:/a:redhat:enterprise_linux:osbuild-composer-core, p-cpe:/a:redhat:enterprise_linux:osbuild-composer-worker, p-cpe:/a:redhat:enterprise_linux:osbuild-composer

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/2/2026

Vulnerability Publication Date: 5/7/2026

Reference Information

CVE: CVE-2026-33818, CVE-2026-39820, CVE-2026-42499, CVE-2026-56853, CVE-2026-56858, CVE-2026-56859, CVE-2026-56860, CVE-2026-56862

CWE: 1046, 1050, 606, 770, 776, 79

RHSA: 2026:62753

Detections

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