# CVE-2026-55677: osbuild-composer: A service for building customized OS artifacts, such as VM images and OSTree commits, that uses osbuild under the hood CVE-2026-55677 is fixed in 4 products on 1 platform, first by RHSA-2026:63134, released June 26, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-55677 - Priority: High - CVSS: 8.2 (important) - EPSS: 0.0052 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 26, 2026 ## Description 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): * golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass (CVE-2026-27136) * golang.org/x/net/html: golang.org/x/net/html: Arbitrary code execution via Cross-Site Scripting (CVE-2026-25681) * golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via unexpected HTML tree rendering (CVE-2026-42502) * github.com/open-telemetry/opentelemetry-go: go.opentelemetry.io/otel/baggage: go.opentelemetry.io/otel/propagation: OpenTelemetry-Go: Denial of Service via oversized baggage headers (CVE-2026-41178) * github.com/labstack/echo: Echo: Unauthorized Information Disclosure via URL Path Decoding Discrepancy (CVE-2026-55677) 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260827T195228-160000.1.1 | [OPENSUSE-SU-2026:21761-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21761-1.md) | Sep 4, 2026 | | Linux | govulncheck-vulndb sles 16.0 | 0.0.20260827T195228-160000.1.1 | [SUSE-SU-2026:23625-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23625-1.md) | Sep 4, 2026 | | Linux | osbuild-composer RHEL 10 | 134.1-10.el10_0 | [RHSA-2026:63134](https://patchblox.com/security/data/fix/linux/rhsa-2026-63134.md) | Jun 26, 2026 | | Linux | osbuild-composer RHEL 8 | 0:101.5-3.el8_10 | [RHSA-2026:67148](https://patchblox.com/security/data/fix/linux/rhsa-2026-67148.md) | Sep 19, 2026 | | Linux | osbuild-composer RHEL 9 | 0:165.1-5.el9_8 | [RHSA-2026:69293](https://patchblox.com/security/data/fix/linux/rhsa-2026-69293.md) | Sep 22, 2026 | | Linux | osbuild-composer almalinux 10 | 165.1-5.el10_2.alma.1 | [ALSA-2026:66432](https://patchblox.com/security/data/fix/linux/alsa-2026-66432.md) | Sep 10, 2026 | | Linux | osbuild-composer almalinux 8 | 101.5-3.el8_10.alma.1 | [ALSA-2026:67148](https://patchblox.com/security/data/fix/linux/alsa-2026-67148.md) | Sep 14, 2026 | | Linux | osbuild-composer almalinux 9 | 165.1-5.el9_8.alma.1 | [ALSA-2026:69293](https://patchblox.com/security/data/fix/linux/alsa-2026-69293.md) | Sep 21, 2026 | | Linux | osbuild-composer ol 10 | 0:176-1.0.3.el10_2 | [ELSA-2026-66432-0](https://patchblox.com/security/data/fix/linux/elsa-2026-66432-0.md) | Sep 14, 2026 | | Linux | osbuild-composer ol 8 | 0:101.5-3.0.1.el8_10 | [ELSA-2026-67148-0](https://patchblox.com/security/data/fix/linux/elsa-2026-67148-0.md) | Sep 28, 2026 | | Linux | osbuild-composer ol 9 | 0:175-1.0.2.el9_8 | [ELSA-2026-69293](https://patchblox.com/security/data/fix/linux/elsa-2026-69293.md) | Nov 7, 2026 | | Linux | osbuild-composer rocky 10 | 0:165.1-5.el10_2.rocky.0.1 | [RLSA-2026:66432](https://patchblox.com/security/data/fix/linux/rlsa-2026-66432.md) | Sep 11, 2026 | | Linux | osbuild-composer rocky 8 | 0:101.5-3.el8_10.rocky.0.6 | [RLSA-2026:67148](https://patchblox.com/security/data/fix/linux/rlsa-2026-67148.md) | Sep 15, 2026 | | Linux | osbuild-composer rocky 9 | 0:165.1-5.el9_8.rocky.0.1 | [RLSA-2026:69293](https://patchblox.com/security/data/fix/linux/rlsa-2026-69293.md) | Sep 22, 2026 | | Linux | osbuild-composer-core RHEL 8 | 0:101.5-3.el8_10 | [RHSA-2026:67148](https://patchblox.com/security/data/fix/linux/rhsa-2026-67148.md) | Sep 19, 2026 | | Linux | osbuild-composer-core RHEL 9 | 0:165.1-5.el9_8 | [RHSA-2026:69293](https://patchblox.com/security/data/fix/linux/rhsa-2026-69293.md) | Sep 22, 2026 | | Linux | osbuild-composer-core almalinux 10 | 165.1-5.el10_2.alma.1 | [ALSA-2026:66432](https://patchblox.com/security/data/fix/linux/alsa-2026-66432.md) | Sep 10, 2026 | | Linux | osbuild-composer-core almalinux 8 | 101.5-3.el8_10.alma.1 | [ALSA-2026:67148](https://patchblox.com/security/data/fix/linux/alsa-2026-67148.md) | Sep 14, 2026 | | Linux | osbuild-composer-core almalinux 9 | 165.1-5.el9_8.alma.1 | [ALSA-2026:69293](https://patchblox.com/security/data/fix/linux/alsa-2026-69293.md) | Sep 21, 2026 | | Linux | osbuild-composer-core ol 10 | 0:176-1.0.3.el10_2 | [ELSA-2026-66432-0](https://patchblox.com/security/data/fix/linux/elsa-2026-66432-0.md) | Sep 14, 2026 | | Linux | osbuild-composer-core ol 8 | 0:101.5-3.0.1.el8_10 | [ELSA-2026-67148-0](https://patchblox.com/security/data/fix/linux/elsa-2026-67148-0.md) | Sep 28, 2026 | | Linux | osbuild-composer-core ol 9 | 0:175-1.0.2.el9_8 | [ELSA-2026-69293](https://patchblox.com/security/data/fix/linux/elsa-2026-69293.md) | Nov 7, 2026 | | Linux | osbuild-composer-worker RHEL 8 | 0:101.5-3.el8_10 | [RHSA-2026:67148](https://patchblox.com/security/data/fix/linux/rhsa-2026-67148.md) | Sep 19, 2026 | | Linux | osbuild-composer-worker RHEL 9 | 0:165.1-5.el9_8 | [RHSA-2026:69293](https://patchblox.com/security/data/fix/linux/rhsa-2026-69293.md) | Sep 22, 2026 | | Linux | osbuild-composer-worker almalinux 10 | 165.1-5.el10_2.alma.1 | [ALSA-2026:66432](https://patchblox.com/security/data/fix/linux/alsa-2026-66432.md) | Sep 10, 2026 | | Linux | osbuild-composer-worker almalinux 8 | 101.5-3.el8_10.alma.1 | [ALSA-2026:67148](https://patchblox.com/security/data/fix/linux/alsa-2026-67148.md) | Sep 14, 2026 | | Linux | osbuild-composer-worker almalinux 9 | 165.1-5.el9_8.alma.1 | [ALSA-2026:69293](https://patchblox.com/security/data/fix/linux/alsa-2026-69293.md) | Sep 21, 2026 | | Linux | osbuild-composer-worker ol 10 | 0:176-1.0.3.el10_2 | [ELSA-2026-66432-0](https://patchblox.com/security/data/fix/linux/elsa-2026-66432-0.md) | Sep 14, 2026 | | Linux | osbuild-composer-worker ol 8 | 0:101.5-3.0.1.el8_10 | [ELSA-2026-67148-0](https://patchblox.com/security/data/fix/linux/elsa-2026-67148-0.md) | Sep 28, 2026 | | Linux | osbuild-composer-worker ol 9 | 0:175-1.0.2.el9_8 | [ELSA-2026-69293](https://patchblox.com/security/data/fix/linux/elsa-2026-69293.md) | Nov 7, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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