Ubuntu kernel update addresses flaws that could compromise the system
Original title: USN-9027-1: Linux kernel vulnerabilities
USN-9027-1 covers x86, hardware monitoring, OCFS2, IPv4, Ethernet bridge, Netfilter and XFRM flaws.
Ubuntu published USN-9027-1 for several Linux kernel security issues that an attacker could possibly use to compromise the system. The fixes span x86 architecture, hardware monitoring drivers, OCFS2, IPv4 networking, the Ethernet bridge, Netfilter and XFRM. Five CVEs are listed. The notice does not describe each flaw, exploitation, or fixed versions.
Unconfirmed: Individual flaw impacts, attack requirements and fixed versions are not stated.
- Listed CVEs are CVE-2025-21656, CVE-2026-63940, CVE-2026-74350, CVE-2026-98432 and CVE-2026-99999.
- Affected areas include OCFS2, IPv4, Netfilter and XFRM.
- The notice says an attacker could possibly compromise the system.
- No fixed versions or exploitation status are given.
Impact: possible compromise of the system
| Product | Affected |
|---|---|
| Ubuntu Linux kernel | — |
- 1.Install the kernel updates referenced in Ubuntu notice USN-9027-1.
- Vendors
- Ubuntu
- Products
- Linux kernel
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2025-21656 | Linux kernel: hwmon: (drivetemp) | 5.5 | <1% | ||
| CVE-2026-63940 | Linux kernel: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count… | 9.3 | <1% | ||
| CVE-2026-74350 | Linux kernel: ocfs2: validate fast symlink target during inode read ocfs2_validate_inode_block() already rejects several… | 9.8 | <1% | ||
CVE-2026-98432+1 related CVE | Use-after-free in Linux kernel IPv4 TCP options | 9.8 group max | <1% | PoC ×25 |
From the original article
Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - x86 architecture; - Hardware monitoring drivers; - OCFS2 file system; - IPv4 networking; - Ethernet bridge; - Netfilter; - XFRM subsystem; (CVE-2025-21656, CVE-2026-63940, CVE-2026-74350, CVE-2026-98432, CVE-2026-99999)
ubuntu.com
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