SB20260728121 - Multiple vulnerabilities in Red Hat OpenShift Container Platform 4.21
Published: July 28, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Memory corruption (CVE-ID: CVE-2026-43329)
CWE-ID: CWE-119 - Memory corruption
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper restriction of operations within the bounds of a memory buffer in flowtable hardware offload action handling when processing IPv6 flowtable offload configurations with multiple actions. A remote attacker can trigger a flow configuration that exceeds the supported number of actions to cause a denial of service.
The issue can be reached in IPv6 setups involving combinations of ethernet mangling, NAT, double VLAN for QinQ, redirect, and tunnel-related actions.
2) Use-after-free (CVE-ID: CVE-2026-46323)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in skb_gro_receive in the GRO subsystem when merging zerocopy skbs. A local user can trigger GRO processing with zerocopy skbs to cause a denial of service.
The issue occurs when either the source skb or the last skb in the GRO chain is zerocopy and uses managed fragment references.
Remediation
Install update from vendor's website.