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RHEL 9 : osbuild-composer (RHSA-2026:91587)
high Nessus Plugin ID 373981
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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-2026:91587 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):
* mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header (CVE-2026-42504)
* google.golang.org/grpc: gRPC-Go: Denial of Service via malformed RPC requests (CVE-2026-84445)
* net/http: golang: golang: Denial of Service via crafted HTTP Range headers (CVE-2026-78667)
* crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references (CVE-2026-97031)
* net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing (CVE-2026-94440)
* net/http: net/http/internal/http2: golang.org/x/net/http2: net/http: Denial of Service via excessive HTTP/2 SETTINGS frames (CVE-2026-78669)
* crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates (CVE-2026-111943)
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-2026:91587.See Also
https://access.redhat.com/errata/RHSA-2026:91587
https://access.redhat.com/security/updates/classification/#important
https://bugzilla.redhat.com/show_bug.cgi?id=2484204
https://bugzilla.redhat.com/show_bug.cgi?id=2533175
https://bugzilla.redhat.com/show_bug.cgi?id=2548334
https://bugzilla.redhat.com/show_bug.cgi?id=2548336
https://bugzilla.redhat.com/show_bug.cgi?id=2548341
https://bugzilla.redhat.com/show_bug.cgi?id=2548344
Plugin Details
Severity: High
ID: 373981
File Name: redhat-RHSA-2026-91587.nasl
Version: 1.1
Type: Local
Agent: unix
Family: Red Hat Local Security Checks
Published: 10/30/2026
Updated: 10/30/2026
Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: High
Score: 7.3
Percentile: 98.16
Vendor
Vendor Severity: Important
CVSS v2
Risk Factor: High
Base Score: 7.1
Temporal Score: 5.3
Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N
CVSS Score Source: CVE-2026-111943
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
CVSS Score Source: CVE-2026-97031
CVSS v4
Risk Factor: High
Base Score: 8.7
Threat Score: 6.6
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score Source: CVE-2026-84445
Vulnerability Information
CPE: cpe:/o:redhat:rhel_eus:9.6, 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: 10/28/2026
Vulnerability Publication Date: 6/2/2026
Reference Information
CVE: CVE-2026-111943, CVE-2026-42504, CVE-2026-78667, CVE-2026-78669, CVE-2026-84445, CVE-2026-94440, CVE-2026-97031
RHSA: 2026:91587