Story · 1 source · 6 articlesfirst Sep 21, 13:04 UTCupdated Sep 25, 11:35 UTC (1d ago)

Ubuntu publishes six Linux kernel security notices in late September

mediumAdvisoryimportance 36CVE-2025-38724 CVE-2026-53131 CVE-2026-53221

What's new: Newest coverage adds USN-8816-1 (2026-09-24), which patches multiple kernel flaws across ARM64, S390, x86, drivers, and filesystems without naming CVEs or reporting exploitation. The other five notices match the prior summary.

Merged summary · grok-4.7 · rewritten as coverage arrives

From Sept. 21–25, 2026, Ubuntu issued six kernel notices fixing IPv6, Netfilter, NFS, and broader flaws; only three CVEs were named, with no exploitation reported.

Ubuntu released six Linux kernel security notices between 2026-09-21 and 2026-09-25. USN-8730-4 (Sept. 21), USN-8730-5 (Sept. 22), and USN-8730-6 (Sept. 25, Intel IoTG kernel) correct flaws in IPv6 networking and Netfilter and do not list CVE identifiers. Separately, USN-8819-1 (Sept. 24) and USN-8819-2 (Sept. 25) also cover the NFS server daemon and cite CVE-2025-38724, CVE-2026-53131, and CVE-2026-53221. USN-8816-1 (Sept. 24) addresses multiple flaws spanning ARM64, S390, and x86 code plus drivers and filesystems including DRBD, InfiniBand, NVMe, MANA, Virtio Host, Xen, NFS, NTFS3, and OCFS2, without naming CVEs. Across the notices Ubuntu says an attacker could, could possibly, or could potentially use the issues to compromise a system; none report observed exploitation. The provided texts do not reconcile which of the three CVEs, if any, correspond to the IPv6 and Netfilter issues in the 8730 series, the NFS issues in the 8819 series, or the broader set in USN-8816-1.

Between 2026-09-21 and 2026-09-25 Ubuntu published six Linux kernel notices: USN-8730-4, USN-8730-5, USN-8730-6, USN-8816-1, USN-8819-1, and USN-8819-2.
USN-8730-4 (2026-09-21) and USN-8730-5 (2026-09-22) correct IPv6 networking and Netfilter flaws and list no CVE identifiers.
USN-8730-6 (2026-09-25) applies those IPv6 and Netfilter fixes to the Intel IoTG kernel, again without CVE IDs.
USN-8819-1 (2026-09-24) and USN-8819-2 (2026-09-25) patch NFS server, IPv6, and Netfilter flaws and cite CVE-2025-38724, CVE-2026-53131, and CVE-2026-53221.
USN-8816-1 (2026-09-24) covers ARM64, S390, and x86 plus drivers and filesystems including DRBD, InfiniBand, NVMe, MANA, Virtio Host, Xen, NFS, NTFS3, and OCFS2, with no CVE IDs.
None of the notices report observed or active exploitation; Ubuntu says an attacker could use the issues to compromise a system, with wording varying from "could" to "could possibly" or "could potentially."
The texts do not map the three named CVEs to specific subsystems, and the 8730 and 8816 notices name no CVEs while the 8819 notices do.

VendorsCanonical Ubuntu

ProductsLinux kernel Ubuntu

MalwareLinux kernel

OrganizationsCanonical Ubuntu Intel

AI modelsLinux kernel

Coverage timelineoldest first · each row is one article

Sep 21, 13:04 UTC · 5d ago
Ubuntu Security Notices· 15
USN-8730-4: Linux kernel vulnerability
Ubuntu patches unspecified vulnerabilities in the Linux kernel's IPv6 and Netfilter components.
Sep 22, 13:19 UTC · 4d ago
Ubuntu Security Notices· 24
USN-8730-5: Linux kernel vulnerability
Ubuntu patches a Linux kernel flaw affecting IPv6 networking and Netfilter that could compromise systems.
Sep 24, 15:00 UTC · 2d ago
Ubuntu Security Notices· 32
USN-8816-1: Linux kernel vulnerabilities
Ubuntu patched multiple Linux kernel flaws across architectures, drivers, and filesystems that could allow system compromise.

Vulnerabilities in this storyAll →

CVE-2025-387247.8<1%
Linux kernel: nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm() Lei Lu recently reported that…
published Sep 4, 2025· linux linux kernel
CVE-2026-532219.8<1%
Linux kernel: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()

CVE	Vulnerability	CVSS	EPSS	Flags	Affected	Exposure	Published
CVE-2025-38724	Linux kernel: nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm() Lei Lu recently reported that… In the Linux kernel, the following vulnerability has been resolved: nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm() Lei Lu recently reported that nfsd4_setclientid_confirm() did not check the return value from get_client_locked(). a SETCLIENTID_CONFIRM could race with a confirmed client expiring and fail to get a reference. That could later lead to a UAF. Fix this by getting a reference early in the case where there is an extant confirmed client. If that fails then treat it as if there were no confirmed client found at all. In the case where the unconfirmed client is expiring, just fail and return the result from get_client_locked(). NVD description · AI analysis pending	7.8	<1%		linux linux kernel linux debian linux	—	Sep 4, 2025
CVE-2026-53221 +1 related CVE CVE-2026-53131	Linux kernel: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() In the Linux kernel, the following vulnerability has been resolved: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: - Tunnels matching the packet's local address, with any remote address wildcard remote). - Tunnels matching the packet's remote address, with any local address (wildcard local). However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions. The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address. NVD description · AI analysis pending	9.8 group max	<1%		linux linux kernel	—	Jun 25, 2026