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Vulnerability · Published Jul 25, 2026 · Assigned by Linux

CVE-2026-64391ksmbd: use opener credentials for ADS I/O

Critical 9.8

In plain English

A critical-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 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 57.6% 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: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2026-64391
Debian:13linux6.12.96-1DEBIAN-CVE-2026-64391
Debian:14linux7.1.4-1DEBIAN-CVE-2026-64391
Debian:12linux-6.126.12.100-1~deb12u1DEBIAN-CVE-2026-64391
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux6.8.0-147.147UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-aws6.8.0-1067.70UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure6.8.0-1071.79UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1069.76UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gcp6.8.0-1071.79UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gke6.8.0-1066.74UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1052.56UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-ibm6.8.0-1067.68UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-147.147.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1035.38UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oracle6.8.0-1064.67UBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64391
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-64391
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-64391
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2026-64391

Affected products (as reported)

VendorProductVersions
Linux Linux f44158485826c076335d6860d35872271a83791d – before 222c4c52c3af2d0f68de31182710df3508a31095f44158485826c076335d6860d35872271a83791d – before 2ad5509dd576ae16d252d4698daf03002f9e0234f44158485826c076335d6860d35872271a83791d – before a8f5d39971bbad9340d49cd41b0e2da9452a649df44158485826c076335d6860d35872271a83791d – before 2b4592cea214683de0f2ce6f8c22c097fb0ea1abf44158485826c076335d6860d35872271a83791d – before 52a56cf53ec834c44ac1b4d16d585f26613ee5cef44158485826c076335d6860d35872271a83791d – before baa5e094886fffa7e6272edcb5e08be5ce28262c
Linux Linux 5.15

References