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Red Hat · Security advisory · June 26, 2026
Red Hat · Security advisory · June 26, 2026RHSA-2026:63134: osbuild-composer security update
RHSA-2026:63134, released June 26, 2026, fixes 5 CVEs in osbuild-composer (version 134.1-10.el10_0). None of them is reported as exploited. Patch Radar priority: Urgent.
Urgent
CVEs closed
5
1 rated Critical
Exploited
0
None reported
Highest CVSS
10.0
Base score, 0 to 10
Highest EPSS
0.0183
79th percentile
Priority of the 5 CVEs
Patch now 0
Urgent 1
High 4
Routine 0
Fixed package versions
| Product | Release | Fixed in |
|---|---|---|
| osbuild-composer | RHEL 10 | 134.1-10.el10_0 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| Urgent | CVE-2026-39821 | Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna | 10.0 | 0.0183 | None reported |
| High | 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 | 8.2 | 0.0052 | None reported |
| High | CVE-2026-25681 | Invoking incorrect handling of character references in DOCTYPE nodes in golang.org/x/net/html | 8.7 | 0.0022 | None reported |
| High | CVE-2026-27136 | Invoking duplicate attributes can cause XSS in golang.org/x/net/html | 8.7 | 0.0022 | None reported |
| High | CVE-2026-42502 | Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html | 8.2 | 0.0022 | None reported |
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