SB2026072962 - Multiple vulnerabilities in Red Hat OpenShift Container Platform 4.18
Published: July 29, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Memory corruption (CVE-ID: CVE-2026-43329)
CWE-ID: CWE-119 - Memory corruption
CVSSv4: 8.7 [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]
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: 6.8 [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]
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.
3) Use-after-free (CVE-ID: CVE-2026-53359)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6.8 [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]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in the KVM x86 shadow paging logic when changing a PDE mapping from outside the guest and deleting a memslot. A local user can trigger stale rmap entries and subsequent dereference of a freed sptep to cause a denial of service.
The issue occurs when a modified PDE points to a non-leaf page, causing a role mismatch between reused shadow pages for large 2MB mappings and new 4KB mappings.
Remediation
Install update from vendor's website.