RHSA-2026:66327: osbuild-composer security update

RHSA-2026:66327, released September 10, 2026, fixes 11 CVEs in osbuild-composer (version 134.1-12.el10_0). None of them is reported as exploited. Patch Radar priority: High.

High

CVEs closed

None rated Critical

Exploited

None reported

Highest CVSS

9.1

Base score, 0 to 10

Highest EPSS

0.0080

56th percentile

Priority of the 11 CVEs

Patch now 0
                                Urgent 0
                                High 11
                                Routine 0

Fixed package versions

Product	Release	Fixed in
osbuild-composer	RHEL 10	134.1-12.el10_0

CVEs this fix closes

Priority	CVE	Title	CVSS	EPSS	Exploitation
High	CVE-2026-42499	Quadratic string concatenation in consumePhrase in net/mail	8.8	0.0080	None reported
High	CVE-2026-39820	Quadratic string concatentation in consumeComment in net/mail	8.8	0.0078	None reported
High	CVE-2026-33818	Enforce maximum recursion depth in encoding/asn1	8.8	0.0057	None reported
High	CVE-2026-56853	Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http	8.8	0.0057	None reported
High	CVE-2026-56859	Add recursion depth guard during decode in encoding/xml	8.8	0.0057	None reported
High	CVE-2026-56862	Limit handshake messages we are willing to accept post-handshake in crypto/tls	8.8	0.0057	None reported
High	CVE-2026-42504	Quadratic complexity in WordDecoder.DecodeHeader in mime	8.8	0.0056	None reported
High	CVE-2026-56860	Avoid quadratic complexity in resolvePath in net/url	8.8	0.0055	None reported
High	CVE-2026-33810	Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509	9.1	0.0035	None reported
High	CVE-2026-41178	opentelemetry-collector: OpenTelemetry-Go is the Go implementation of OpenTelemetry	8.2	0.0034	None reported
High	CVE-2026-56858	Fix Javascript regexp context tracking in html/template	8.8	0.0031	None reported

Also fixes CVE-2026-42499

OPENSUSE-SU-2026:21483-1
govulncheck-vulndb on opensuse-leap 16.0
RHSA-2026:67517
grafana on RHEL 10
RHSA-2026:49702
golang on RHEL 10
ELSA-2026-65534-0
image-builder on ol 10
RHSA-2026:65534
image-builder on RHEL 10
RLSA-2026:65534
image-builder on rocky 10
RHSA-2026:65886
image-builder on RHEL 9
ELSA-2026-65886-0
image-builder on ol 9

Vendor advisory

https://access.redhat.com/errata/RHSA-2026:66327

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