Red Hat Security Advisory: osbuild-composer security update
Affects Red Hat osbuild-composerSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High : upgrade Red Hat http to 1.27.2 or 1.26.9 soon.
Data as of 12 Nov 2026, 20:42 UTC
- Patch
- Available – fixed in 1.27.2, 1.26.9
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.
What to do
Upgrade net/http to 1.27.2 or 1.26.9.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Go standard librarynet/http | Affected
| Fixed in
|
| Go standard librarynet/http | Affected
| Fixed in
|
Gonet/httppkg:golang/net/httpOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released updated osbuild-composer packages for Red Hat Enterprise Linux 8.6 Extended Life Cycle Long Life and AUS variants that fix these denial of service vulnerabilities. Users should apply the provided security update as detailed in the Red Hat advisory RHSA-2026:99758. No additional mitigation steps are indicated by the vendor.
Description
Red Hat has issued a security update for osbuild-composer, a service used to build customized OS artifacts including VM images and OSTree commits. The update addresses multiple denial of service vulnerabilities in various Golang components used by osbuild-composer, such as gRPC, net/http, crypto/tls, and multipart form parsing. These vulnerabilities could allow denial of service attacks via malformed RPC requests, crafted HTTP Range headers, multiple ECH outer extension references, memory limit bypass in multipart parsing, and excessive HTTP/2 SETTINGS frames. The update is rated as important by Red Hat and applies to Red Hat Enterprise Linux 8.6 variants.
References
- access.redhat.com/errata/RHSA-2026:99758 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2533175 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2548334 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2548336 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2548341 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2548344 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_99758.json (opens in a new tab)