Red Hat Security Advisory: kernel security update
The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: Linux kernel:A use-after-free in bridge multicast in br_multicast_port_ctx_init (CVE-2025-38248) * kernel: Bluetooth: MGMT: Fix possible UAFs (CVE-2025-39981) * kernel: mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats (CVE-2025-68800) * kernel: Linux kernel: Denial of Service via unsafe requeue in rxrpc_recvmsg (CVE-2026-23066) * kernel: Linux kernel: Local denial of service and memory leak in DAMON sysfs via setup failure (CVE-2026-23144) * kernel: Linux kernel: Use-after-free in bonding module can cause system crash or arbitrary code execution (CVE-2026-23171) * kernel: macvlan: fix error recovery in macvlan_common_newlink() (CVE-2026-23209) * kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) * kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) 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.
AI Analysis
Technical Summary
CVE-2025-38248 is a use-after-free vulnerability in the Linux kernel's bridge multicast initialization function (br_multicast_port_ctx_init) that can lead to privilege escalation. This affects Container-Optimized OS and Ubuntu nodes running in Google Kubernetes Engine (GKE) Standard clusters, with potential impact on Autopilot clusters configured with unconfined seccomp or CAP_NET_ADMIN. GKE Sandbox clusters and GDC bare metal software are not affected. Red Hat Enterprise Linux 9.6 Extended Update Support kernel packages include fixes for this vulnerability. The Red Hat advisory (RHSA-2026:5197) also addresses a related use-after-free in macvlan (CVE-2026-23001). Patch versions for affected GKE node pools are provided, with instructions to upgrade to specific patch versions or later. For some GKE platforms (AWS, Azure, VMware), patch details are pending. The Red Hat update requires a reboot to take effect.
Potential Impact
Successful exploitation of CVE-2025-38248 can lead to privilege escalation on affected nodes, potentially allowing attackers to gain elevated privileges within the node's operating system. This impacts Container-Optimized OS and Ubuntu nodes in GKE Standard clusters and certain Autopilot cluster configurations. GKE Sandbox clusters and GDC bare metal software are not affected. Red Hat Enterprise Linux 9.6 Extended Update Support users are also impacted but have an available kernel update. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
For GKE users, upgrade Container-Optimized OS and Ubuntu node pools to the specified patch versions or later as listed in the advisory. Avoid using unconfined seccomp profiles or granting CAP_NET_ADMIN capability in Autopilot clusters to reduce exposure. For Red Hat Enterprise Linux 9.6 Extended Update Support, apply the kernel update provided in advisory RHSA-2026:5197 and reboot the system to activate the patch. For GKE on AWS, Azure, and VMware, monitor vendor advisories for forthcoming patch releases. No action is required for GDC bare metal software as it is not affected.
Red Hat Security Advisory: kernel security update
Description
The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: Linux kernel:A use-after-free in bridge multicast in br_multicast_port_ctx_init (CVE-2025-38248) * kernel: Bluetooth: MGMT: Fix possible UAFs (CVE-2025-39981) * kernel: mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats (CVE-2025-68800) * kernel: Linux kernel: Denial of Service via unsafe requeue in rxrpc_recvmsg (CVE-2026-23066) * kernel: Linux kernel: Local denial of service and memory leak in DAMON sysfs via setup failure (CVE-2026-23144) * kernel: Linux kernel: Use-after-free in bonding module can cause system crash or arbitrary code execution (CVE-2026-23171) * kernel: macvlan: fix error recovery in macvlan_common_newlink() (CVE-2026-23209) * kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) * kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) 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.
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2025-38248 is a use-after-free vulnerability in the Linux kernel's bridge multicast initialization function (br_multicast_port_ctx_init) that can lead to privilege escalation. This affects Container-Optimized OS and Ubuntu nodes running in Google Kubernetes Engine (GKE) Standard clusters, with potential impact on Autopilot clusters configured with unconfined seccomp or CAP_NET_ADMIN. GKE Sandbox clusters and GDC bare metal software are not affected. Red Hat Enterprise Linux 9.6 Extended Update Support kernel packages include fixes for this vulnerability. The Red Hat advisory (RHSA-2026:5197) also addresses a related use-after-free in macvlan (CVE-2026-23001). Patch versions for affected GKE node pools are provided, with instructions to upgrade to specific patch versions or later. For some GKE platforms (AWS, Azure, VMware), patch details are pending. The Red Hat update requires a reboot to take effect.
Potential Impact
Successful exploitation of CVE-2025-38248 can lead to privilege escalation on affected nodes, potentially allowing attackers to gain elevated privileges within the node's operating system. This impacts Container-Optimized OS and Ubuntu nodes in GKE Standard clusters and certain Autopilot cluster configurations. GKE Sandbox clusters and GDC bare metal software are not affected. Red Hat Enterprise Linux 9.6 Extended Update Support users are also impacted but have an available kernel update. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
For GKE users, upgrade Container-Optimized OS and Ubuntu node pools to the specified patch versions or later as listed in the advisory. Avoid using unconfined seccomp profiles or granting CAP_NET_ADMIN capability in Autopilot clusters to reduce exposure. For Red Hat Enterprise Linux 9.6 Extended Update Support, apply the kernel update provided in advisory RHSA-2026:5197 and reboot the system to activate the patch. For GKE on AWS, Azure, and VMware, monitor vendor advisories for forthcoming patch releases. No action is required for GDC bare metal software as it is not affected.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:9644
- Cve Count
- 9
- Additional Cves
- ["CVE-2025-39981","CVE-2025-68800","CVE-2026-23066","CVE-2026-23144","CVE-2026-23171","CVE-2026-23204","CVE-2026-23209","CVE-2026-23231"]
Threat ID: 6a18be67e29bf47b503872cd
Added to database: 05/28/2026, 22:15:03 UTC
Last enriched: 08/04/2026, 13:07:01 UTC
Last updated: 09/11/2026, 22:06:29 UTC
Views: 110
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