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CVE-2026-33186VulnerabilityPublished Updated

Red Hat Security Advisory: osbuild-composer security update

Affects Red Hat osbuild-composerSource GCVE Database

0

Mentioned vulnerabilities

Authoritative record:CVE-2026-33186· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical : upgrade Red Hat grpc-go to 1.79.3 as a priority.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.5% chance of exploitation in 30 days – higher than 75% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.79.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 26 Oct 2026.

What to do

Upgrade grpc-go and github.com/grpc/grpc-go to 1.79.3.

Affected software

ProductAffectedFixed in
grpcgrpc-goAffected
  • <1.79.3
Fixed in
  • 1.79.3
Gogithub.com/grpc/grpc-gopkg:golang/github.com/grpc/grpc-goOther threatsAffected
  • <1.79.3
Fixed in
  • 1.79.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

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): * google.golang.org/grpc/grpc-go: google.golang.org/grpc/authz: gRPC-Go: Authorization bypass due to improper HTTP/2 path validation (CVE-2026-33186) * golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821) 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.

References

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