SB2026090302 - Red Hat Enterprise Linux 8 update for kernel-rt
Published: September 3, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 14 vulnerabilities.
1) Use-after-free (CVE-ID: CVE-2024-57849)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the cpumsf_pmu_stop() function in arch/s390/kernel/perf_cpum_sf.c. A local user can escalate privileges on the system.
2) Memory leak (CVE-ID: CVE-2025-71132)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
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 perform a denial of service (DoS) attack.
The vulnerability exists due to memory leak within the smc_rcv() function in drivers/net/ethernet/smsc/smc91x.c. A local user can perform a denial of service (DoS) attack.
3) Use-after-free (CVE-ID: CVE-2026-45970)
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 rlb_arp_recv function in the bonding ALB RX path when processing ARP messages during rapid bond up/down cycles. A local user can trigger concurrent bond up/down operations while ARP traffic is being received to cause a denial of service.
The issue is triggered by a race condition between rlb_arp_recv() and rlb_deinitialize().
4) Use-after-free (CVE-ID: CVE-2026-53185)
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 use-after-free in zram_bvec_write_partial() when processing partial writes for ZRAM_WB slots. A local user can trigger an asynchronous backing device read and subsequent access to a freed page to cause a denial of service.
The issue occurs because the read operation may still be in flight when the buffer page is freed.
5) Use-after-free (CVE-ID: CVE-2026-63800)
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 use-after-free in pnfs_update_layout() when handling the NFS_LAYOUT_RETURN branch. A local user can trigger the vulnerable code path to cause a denial of service.
6) Memory leak (CVE-ID: CVE-2026-53397)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a memory leak in the nfsd SETACL request decoding and release handling when processing crafted NFS ACL SETACL requests. A remote user can send a specially crafted SETACL request that triggers a decode failure after partial ACL allocation to cause a denial of service.
The leaked posix_acl object remains allocated for the lifetime of the server.
7) Use-after-free (CVE-ID: CVE-2026-53399)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a use-after-free in the nfsd layout stateid handling in fs/nfsd/nfs4layouts.c when processing layout stateid allocation failures after a setlease error. A remote user can trigger a setlease failure and subsequent IDR walker access to dereference a dangling pointer to cause a denial of service.
The issue occurs because a published stateid remains referenced in the IDR after the associated memory is freed, and a related destructor path may access uninitialized delayed work on the same failure path.
8) Improper input validation (CVE-ID: CVE-2026-53392)
CWE-ID: CWE-20 - Improper input validation
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 input validation in ff_layout_alloc_lseg() in the NFSv4 flexfiles layout handling when processing a malformed flexfiles layout body with a zero filehandle-version array count. A remote attacker can send a specially crafted flexfiles layout to cause a denial of service.
The issue can lead to a null pointer dereference and kernel panic.
9) NULL pointer dereference (CVE-ID: CVE-2026-53391)
CWE-ID: CWE-476 - NULL Pointer Dereference
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 a NULL pointer dereference in nfs4_decode_mp_ds_addr() when processing a crafted GETDEVICEINFO multipath-DS body containing a zero-length r_addr or r_netid value. A remote attacker can send malicious metadata server responses to cause a denial of service.
The issue is reachable from a pNFS-flexfile client mounted against a malicious or compromised metadata server.
10) Out-of-bounds read (CVE-ID: CVE-2026-64018)
CWE-ID: CWE-125 - Out-of-bounds read
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 attacker to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in mana_hwc_rx_event_handler() when processing hardware-modifiable WQE contents from DMA-coherent memory. A local attacker can modify the derived rx_req_idx value to cause a denial of service.
In confidential VMs such as SEV-SNP and TDX, the affected DMA-coherent memory is shared unencrypted and hardware can modify WQE contents at any time.
11) Out-of-bounds write (CVE-ID: CVE-2026-64268)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 7.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to write out of bounds.
The vulnerability exists due to an out-of-bounds write in siw_proc_rresp() in drivers/infiniband/sw/siw/siw_qp_rx.c when processing Read Response DDP segments for an outstanding RREAD over an established RDMA connection. A remote user can send Read Response segments with more total payload than requested while keeping the DDP Last flag clear to write out of bounds.
Exploitation requires a connected siw peer on an established RDMA connection over routable TCP.
12) Improper access control (CVE-ID: CVE-2026-64298)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to bypass file write permission checks and truncate a file.
The vulnerability exists due to improper access control in nfs_open_permission_mask() when handling open requests with O_TRUNC on NFSv4 delegated opens. A local user can open a file with O_RDONLY | O_TRUNC to bypass file write permission checks and truncate a file.
This issue occurs when the client satisfies the OPEN locally from a cached write delegation and then sends truncation to the server using delegation state.
13) Insufficient Control Flow Management (CVE-ID: CVE-2026-68480)
CWE-ID: CWE-691 - Insufficient Control Flow Management
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to improper control flow handling in the x86 Safe-RET sequence when interrupts are injected during execution of the sequence on SRSO-affected systems. A local user can inject interrupts during the Safe-RET sequence to disclose sensitive information.
Only systems affected by SRSO are vulnerable.
14) Use-after-free (CVE-ID: CVE-2026-74581)
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 fib6_rule_lookup() and fib6_rule_suppress() in the IPv6 routing rules handler when processing suppressed IPv6 route lookups. A local user can trigger route lookups involving a suppressing rule to cause a denial of service.
The issue occurs because a stale dst entry can be returned after the released route remains referenced in the lookup result.
Remediation
Install update from vendor's website.