SB2026092444 - Red Hat Enterprise Linux 8 update for kernel
Published: September 24, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 6 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) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-53266) Exploited
CWE-ID: CWE-664 - Improper control of a resource through its lifetime
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 improper memory handling in the ebtables SNAT target ARP sender hardware address rewrite in net/bridge/netfilter/ebt_snat.c when processing ARP packets in bridge netfilter hooks. A local user can trigger ARP sender hardware address rewriting on a crafted nonlinear skb to cause a denial of service.
Exploitation requires the ARP sender hardware address rewrite path to be reached with a nonlinear skb fragment backed by a splice-imported file page.
3) Use-after-free (CVE-ID: CVE-2026-68121)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 5.8 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause memory corruption.
The vulnerability exists due to a use-after-free in pppoe_sendmsg() when handling a blocked send while a non-Ethernet port is added to an empty team device. A local user can trigger skb head reallocation and subsequent writes through a stale PPPoE header pointer to cause memory corruption.
The issue occurs because device header callbacks may reallocate the skb head and invalidate saved pointers into it.
4) Out-of-bounds write (CVE-ID: CVE-2026-74469)
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 SCTP sock_diag when processing a diagnostic dump after adding many unique peer transports. A local user can add unique peer addresses until the 16-bit transport_count wraps and trigger a diagnostic dump to cause a denial of service.
The issue occurs when the association accumulates 65,536 unique peer transports, causing transport_count to wrap to zero while peer addresses are still copied from transport_addr_list.
5) Improper Validation of Specified Quantity in Input (CVE-ID: CVE-2026-80844)
CWE-ID: CWE-1284 - Improper Validation of Specified Quantity in Input
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause an out-of-bounds memory access.
The vulnerability exists due to improper validation of routing header segments_left values in ipv6_rearrange_rthdr() when processing raw IPv6 HDRINCL packets with a segments_left value larger than the number of addresses described by hdrlen. A local user can send a crafted packet with an oversized segments_left value to cause an out-of-bounds memory access.
6) Integer underflow (CVE-ID: CVE-2026-81000)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a local user to write packet data outside allocated memory.
The vulnerability exists due to an integer underflow in TUN and TAP interface handling in tun_get_user() when processing an oversized headroom request propagated by an OVS port. A local user can configure an OVS port to propagate an oversized headroom request to a TUN or TAP device to write packet data outside allocated memory.
Remediation
Install update from vendor's website.