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Vulnerability · Published Oct 14, 2026 · Assigned by Linux

CVE-2026-98405smb: client: fix missing iov bounds check in parse_posix_sids()

High 8.1

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.5%top 58.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix missing iov bounds check in parse_posix_sids() In parse_posix_sids(), sidsbuf_end is calculated using the server-supplied out_len without being validated against the actual length of the received iov (iov_len). If a server provides an inflated out_len, sidsbuf_end will point past the end of the iov. This defeats the bounds guards in posix_info_sid_size(), allowing out-of-bounds reads into adjacent kernel memory. Fix this by rejecting responses where the calculated sidsbuf_end would exceed the received iov boundaries or cause pointer wraparound.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-98405
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-98405
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-98405

Affected products (as reported)

VendorProductVersions
Linux Linux a90f37e3d7acfd9824f162830583bbf7846fe252 – before d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644858e74876c5cbff1dfd5bace99e32fbce2abd4b5 – before b862996e5105be1293da9cdc85da77b76021c3bd858e74876c5cbff1dfd5bace99e32fbce2abd4b5 – before 2f8ed71aaaba3bc8b19cd9930cc62e63e142b299858e74876c5cbff1dfd5bace99e32fbce2abd4b5 – before eac6917a42899aad0617bbf04798c5dd946a1fe5858e74876c5cbff1dfd5bace99e32fbce2abd4b5 – before b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc6.6.32 – before 6.6.158
Linux Linux 6.8

References