SB2026092407 - Red Hat Enterprise Linux 9 update for kernel
Published: September 24, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 13 vulnerabilities.
1) Race condition (CVE-ID: CVE-2025-39964) Exploited
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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 race condition within the include/crypto/if_alg.h. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.
2) Race condition (CVE-ID: CVE-2026-45894)
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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 race condition in the Intel VT-d scalable mode PASID table entry handling when tearing down an active PASID entry. A local user can trigger concurrent PASID entry teardown to cause a denial of service.
The issue can lead to unpredictable behavior or spurious faults if the IOMMU hardware observes a torn read of the entry.
3) Release of invalid pointer or reference (CVE-ID: CVE-2026-45959)
CWE-ID: CWE-763 - Release of invalid pointer or reference
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 invalid free in the ccp crypto component when performing cleanup of a local pointer annotated with __cleanup(kfree). A local attacker can trigger the vulnerable code path to cause a denial of service.
4) Use-after-free (CVE-ID: CVE-2026-53062)
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 the dm-cache smq policy invalidate_mapping operation when handling concurrent writes in passthrough mode. A local user can trigger concurrent cache block invalidations to cause a denial of service.
The issue occurs when the cache is operating in passthrough mode and multiple workers invalidate cache blocks simultaneously.
5) Use-after-free (CVE-ID: CVE-2026-63823)
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 request_key_auth handling in the Linux kernel key management subsystem when processing KEYCTL_INSTANTIATE_IOV or related key instantiation and rejection paths concurrently with request_key() completion. A local user can trigger concurrent key operations to cause a denial of service.
The issue occurs because the request_key_auth payload can be freed after helper completion while another path later resumes and accesses rka->target_key.
6) Out-of-bounds read (CVE-ID: CVE-2026-68293)
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 user to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in the MCIA register handling in the mlx5 driver when processing module EEPROM reads via ethtool. A local user can trigger a read of module EEPROM data to cause a denial of service.
The issue is detected on kernels built with FORTIFY_SOURCE, where it results in a kernel BUG.
7) NULL pointer dereference (CVE-ID: CVE-2026-68157)
CWE-ID: CWE-476 - NULL Pointer Dereference
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 null pointer dereference in get_immediate_parent() in net/ceph/osdmap.c when processing malformed CRUSH hierarchy metadata during localized read selection. A local user can trigger lookup of a parent bucket whose type has no matching entry in type_names to cause a denial of service.
The issue occurs when a parent bucket name exists in the CRUSH map but its type name metadata is missing, causing an invalid pointer to be passed to strcmp().
8) Use-after-free (CVE-ID: CVE-2026-68188)
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 cause a denial of service or execute arbitrary code.
The vulnerability exists due to use-after-free in rfcomm_tty_set_termios() and rfcomm_send_rpn() when handling TTY ioctl requests on an RFCOMM device during a concurrent session teardown. A local user can trigger a race condition to cause a denial of service or execute arbitrary code.
The issue is caused by concurrent access to dlc->session without proper locking while krfcommd can unlink the DLC and free the associated session.
9) Use-after-free (CVE-ID: CVE-2026-68156)
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 the Ceph authorizer handling code when processing a rebuilt authorizer during a messenger reconnect. A local user can trigger an authorizer update that reallocates the buffer and then cause a reconnect to use a stale pointer to cause a denial of service.
The issue is triggered when a newer service ticket causes the authorizer to be rebuilt and the rebuilt authorizer no longer fits in the existing buffer.
10) Improper input validation (CVE-ID: CVE-2026-68155)
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 ceph_monmap_decode() when processing a CEPH_MSG_MON_MAP monmap message. A remote attacker can send a specially crafted monmap advertising zero monitors to cause a denial of service.
The issue is triggered when the client later attempts to open a session with a monitor, causing an assertion in pick_new_mon() to fire.
11) Use-after-free (CVE-ID: CVE-2026-68391)
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 the Bluetooth management subsystem in net/bluetooth/mgmt.c when handling Bluetooth management operations involving pending command callbacks and connection lookups. A local user can trigger connection state changes during these operations to cause a denial of service.
The issue involves dereferencing RCU-protected hci_conn pointers outside critical sections and accessing connection state without the required device lock, which can also lead to a data race.
12) Use-after-free (CVE-ID: CVE-2026-72072)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/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 mlx5e MACsec RX offload handling when deleting and processing offloaded MACsec RX SC entries concurrently. A local user can trigger concurrent RX SC deletion and RX datapath processing to cause a denial of service.
The issue affects the RX datapath under RCU lookup and reference handling of metadata_dst objects.
13) Use-after-free (CVE-ID: CVE-2026-74518)
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 allocate_file_region_entries() when handling concurrent region cache operations on a shared resv_map. A local user can trigger concurrent region_chg()/region_add()/region_del() activity on the same shared mapping to cause a denial of service.
The issue occurs in shared hugetlbfs mappings and was observed when multiple mappers accessed the same hugetlbfs inode concurrently.
Remediation
Install update from vendor's website.