SB2026082606 - Red Hat Enterprise Linux 8 update for kernel-rt
Published: August 26, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 8 vulnerabilities.
1) Use-after-free (CVE-ID: CVE-2026-52924)
CWE-ID: CWE-416 - Use After Free
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 use-after-free in the SCTP outqueue and stream scheduler state handling when processing a stale COOKIE-ECHO condition. A remote attacker can send a stale cookie error during SCTP association handling to cause a denial of service.
The issue occurs when an association is rolled back from COOKIE_ECHOED to COOKIE_WAIT, leaving scheduler state referencing freed stream entries.
2) Heap-based buffer overflow (CVE-ID: CVE-2026-63886)
CWE-ID: CWE-122 - Heap-based Buffer Overflow
CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/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 heap-based buffer overflow in chap_server_compute_hash() in the iSCSI target CHAP authentication handling when processing a specially crafted base64-encoded CHAP_R response. A remote user can send a specially crafted CHAP authentication response to cause a denial of service.
The issue affects the BASE64 CHAP_R decoding path; the mutual CHAP CHAP_C decoding path is not affected.
3) Insufficient verification of data authenticity (CVE-ID: CVE-2026-63913)
CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper state validation in the TCP conntrack state machine in netfilter conntrack when processing a crafted SYN followed by an invalid-sequence RST packet. A remote attacker can send a specially crafted packet sequence to cause a denial of service.
The issue can prematurely terminate an active NAT entry by forcing the conntrack entry into the CLOSE state.
4) Out-of-bounds read (CVE-ID: CVE-2026-64191)
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 out-of-bounds read and out-of-bounds write in stub_xfer() in the i2c-stub driver when handling an I2C_SMBUS ioctl with I2C_SMBUS_I2C_BLOCK_DATA and an invalid block length. A local user can issue a crafted ioctl request with data->block[0] greater than 32 to cause a denial of service.
The issue affects the development and test i2c-stub driver, which is not built by default and must be loaded with a chip_addr= parameter.
5) Use-after-free (CVE-ID: CVE-2026-64189)
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 ip_set_dump_do() and ip_set_dump_done() in the ipset netfilter subsystem when handling netlink dump operations concurrently with ip_set_list resizing. A local user can trigger concurrent netlink dump and set creation operations to cause a denial of service.
The issue can lead to a general protection fault and kernel panic.
6) Out-of-bounds read (CVE-ID: CVE-2026-64320)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to disclose sensitive information or cause a denial of service.
The vulnerability exists due to an out-of-bounds heap read in nvmet_execute_disc_get_log_page() in the NVMe target discovery controller when handling a host-supplied log page offset in a Discovery Get Log Page request. A remote attacker can send a specially crafted request with an out-of-range offset to disclose sensitive information or cause a denial of service.
The issue is reachable before authentication by any TCP, RDMA, or FC peer that can reach the nvmet target.
7) Out-of-bounds read (CVE-ID: CVE-2026-64277)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to disclose sensitive information and overwrite adjacent kernel memory.
The vulnerability exists due to an out-of-bounds read and out-of-bounds write in the synaptics-rmi4 F3A GPIO keymap handling in drivers/input/rmi4/rmi_f3a.c when processing a device that reports a gpio_count greater than the allocated keymap size. A local user can open the evdev node and invoke keymap ioctls to disclose sensitive information and overwrite adjacent kernel memory.
The information disclosure occurs through EVIOCGKEYCODE leaking adjacent slab memory to user space, while EVIOCSKEYCODE writes a caller-controlled value past the buffer.
8) Out-of-bounds read (CVE-ID: CVE-2026-64276)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service or disclose sensitive information.
The vulnerability exists due to out-of-bounds read and out-of-bounds write in the rmi_f30_attention handler and EVIOCGKEYCODE/EVIOCSKEYCODE ioctl handling in the synaptics-rmi4 F30 driver when processing a device that reports a gpioled_count greater than 6 with GPIO support enabled. A local user can trigger the attention interrupt or use EVIOCGKEYCODE/EVIOCSKEYCODE ioctls to cause a denial of service or disclose sensitive information.
The issue occurs because the keymap allocation is smaller than the gpioled_count value used for iteration and keycode bounds.
Remediation
Install update from vendor's website.