CVE-2026-31611 — ksmbd: require 3 sub-authorities before reading sub_auth[2]

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: require 3 sub-authorities before reading sub_auth[2]

parse_dacl() compares each ACE SID against sid_unix_NFS_mode and on match reads sid.sub_auth[2] as the file mode. If sid_unix_NFS_mode is the prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares only min(num_subauth, 2) sub-authorities so a client SID with num_subauth = 2 and sub_auth = {88, 3} will match.

If num_subauth = 2 and the ACE is placed at the very end of the security descriptor, sub_auth[2] will be 4 bytes past end_of_acl. The out-of-band bytes will then be masked to the low 9 bits and applied as the file's POSIX mode, probably not something that is good to have happen.

Fix this up by forcing the SID to actually carry a third sub-authority before reading it at all.

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some AMD processors did not properly clear data in the floating point divider unit during speculative execution. A local attacker could use this to expose sensitive information. (CVE-2025-54505)

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: - ARM64 architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Rados block device (RBD) driver; - Compressed RAM block device driver; - Character device driver; - TPM device driver; - Hardware crypto device drivers; - EDAC drivers; - GPU drivers; - Greybus drivers; - HID subsystem; - Microsoft Hyper-V drivers; - Hardware monitoring drivers; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - Input Device core drivers; - LED subsystem; - Multiple devices driver; - Media drivers; - IBM Advanced System Management driver; - MTD block device drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - NTB driver; - NVME drivers; - Device tree and open firmware driver; - PCI subsystem; - Remote Processor subsystem; - SCSI subsystem; - SPI subsystem; - Realtek RTL8723BS SDIO drivers; - SM750 framebuffer staging driver; - Thermal drivers; - USB Gadget drivers; - USB over IP driver; - VFIO drivers; - Framebuffer layer; - 9P distributed file system; - AFS file…

Most recent entries from all

CVE-2026-31611 — ksmbd: require 3 sub-authorities before reading sub_auth[2]

USN-8488-1 — linux, linux-aws, linux-gcp, linux-ibm, linux-oracle, linux-realtime vulnerabilities