SB2026082604 - Red Hat Enterprise Linux 9 update for kernel-rt
Published: August 26, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 vulnerabilities.
1) Improper input validation (CVE-ID: CVE-2026-31411)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/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 improper input validation in sigd_send() when handling sendmsg() input containing a forged vcc pointer. A local user can send a specially crafted message to cause a denial of service.
Exploitation requires control of the ATM signaling daemon role via the ATMSIGD_CTRL ioctl.
2) Out-of-bounds read (CVE-ID: CVE-2026-43112)
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 in cifs_sanitize_prepath when parsing path strings containing only delimiters or no path content. A local user can supply a crafted path string to cause a denial of service.
The issue can be triggered by an empty string or a string such as "/".
3) Use-after-free (CVE-ID: CVE-2026-46099)
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 seg6 and rpl lwtunnels when processing IPv6 routing lookups and caching a NOREF destination entry. A local user can trigger a race condition to cause a denial of service.
Exploitation requires PREEMPT_RT without PREEMPT_RT_NEEDS_BH_LOCK and a concurrent task able to release a shared nexthop per-cpu route entry.
4) Out-of-bounds write (CVE-ID: CVE-2026-53059)
CWE-ID: CWE-787 - Out-of-bounds write
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 write in create_log_context() and dm-log bitset handling when processing a crafted device-mapper mirror target configuration with an oversized region count. A local user can create a crafted mirror target to cause a denial of service.
The issue is triggered when region_count overflows 32 bits, causing bitsets to be allocated smaller than required and later accessed with indices derived from the full region space.
Remediation
Install update from vendor's website.