Red Hat Security Advisory: kernel security update
The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: smc: Fix use-after-free in __pnet_find_base_ndev() (CVE-2025-40064) * kernel: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match() (CVE-2025-40168) * kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) * kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
AI Analysis
Technical Summary
The advisory covers four kernel vulnerabilities: CVE-2025-40064 fixes a use-after-free in __pnet_find_base_ndev() within the smc subsystem; CVE-2025-40168 addresses improper use of __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match(); CVE-2026-23204 corrects usage of skb_header_pointer_careful() in net/sched cls_u32; and CVE-2026-23231 resolves a use-after-free that could lead to privilege escalation or denial of service in nf_tables_addchain(). These issues affect Red Hat Enterprise Linux 8.6 variants and are fixed in updated kernel packages. The advisory recommends applying the update and rebooting the system to activate the patches.
Potential Impact
Successful exploitation of these vulnerabilities could lead to use-after-free conditions causing system instability, privilege escalation, or denial of service on affected Red Hat Enterprise Linux 8.6 systems. The overall security impact is rated moderate by Red Hat Product Security. There are no known exploits in the wild at the time of this advisory.
Mitigation Recommendations
Red Hat has released updated kernel packages that address these vulnerabilities. Users should apply the available kernel updates for Red Hat Enterprise Linux 8.6 as detailed in the advisory (RHSA-2026:9514) and reboot affected systems to ensure the fixes take effect. Patch status is official-fix via these updates. No additional mitigations are indicated by the vendor.
Red Hat Security Advisory: kernel security update
Description
The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: smc: Fix use-after-free in __pnet_find_base_ndev() (CVE-2025-40064) * kernel: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match() (CVE-2025-40168) * kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) * kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The advisory covers four kernel vulnerabilities: CVE-2025-40064 fixes a use-after-free in __pnet_find_base_ndev() within the smc subsystem; CVE-2025-40168 addresses improper use of __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match(); CVE-2026-23204 corrects usage of skb_header_pointer_careful() in net/sched cls_u32; and CVE-2026-23231 resolves a use-after-free that could lead to privilege escalation or denial of service in nf_tables_addchain(). These issues affect Red Hat Enterprise Linux 8.6 variants and are fixed in updated kernel packages. The advisory recommends applying the update and rebooting the system to activate the patches.
Potential Impact
Successful exploitation of these vulnerabilities could lead to use-after-free conditions causing system instability, privilege escalation, or denial of service on affected Red Hat Enterprise Linux 8.6 systems. The overall security impact is rated moderate by Red Hat Product Security. There are no known exploits in the wild at the time of this advisory.
Mitigation Recommendations
Red Hat has released updated kernel packages that address these vulnerabilities. Users should apply the available kernel updates for Red Hat Enterprise Linux 8.6 as detailed in the advisory (RHSA-2026:9514) and reboot affected systems to ensure the fixes take effect. Patch status is official-fix via these updates. No additional mitigations are indicated by the vendor.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:9514
- Cve Count
- 4
- Additional Cves
- ["CVE-2025-40168","CVE-2026-23204","CVE-2026-23231"]
- Cvss Version
- null
Threat ID: 6a27e9f98dd33fbd8517c171
Added to database: 06/09/2026, 10:24:57 UTC
Last enriched: 07/12/2026, 10:20:04 UTC
Last updated: 07/31/2026, 19:24:46 UTC
Views: 311
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.