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Vulnerability · Published Oct 6, 2026 · Assigned by Linux

CVE-2026-98171smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs

High 8.8

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 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 54.6% 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 next_buffer UAF and NextCommand bounds in compound PDUs Fix several related bounds checking and pointer lifecycle issues in receive_encrypted_standard()'s handling of compound encrypted frames: - Clear next_buffer after assigning it to server->bigbuf. A stale next_buffer pointer can lead to a use-after-free on subsequent error paths. - Update pdu_length to the decrypted plaintext size (buf_size). Using the pre-decryption length allows NextCommand to point into stale ciphertext residue. - Reject next_cmd values smaller than MID_HEADER_SIZE(server). - Fix an integer overflow in the upper bound check by verifying pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the trailing slice is large enough for a header.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.190-1DEBIAN-CVE-2026-98171
Debian:13linux6.12.113-1DEBIAN-CVE-2026-98171
Debian:14linux7.2.8-1DEBIAN-CVE-2026-98171
Debian:12linux-6.126.12.113-1~deb12u1DEBIAN-CVE-2026-98171
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux7.0.0-42.42UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-aws7.0.0-1016.17UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-aws-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-fde-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-gcp7.0.0-1016.18UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gcp-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-42.42~24.04.1UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-ibm7.0.0-1017.17UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidia-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-nvidia-bosno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1017.17UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-oracle7.0.0-1015.16UBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-oracle-7.0no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98171
Ubuntu:26.04:LTSlinux-riscv7.0.0-42.42.1UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-42.42.1~24.04.1UBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-vmwareno fix listedUBUNTU-CVE-2026-98171
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-98171
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2026-98171

Affected products (as reported)

VendorProductVersions
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 1ed29f7a03417b405f38c09cfe04124883127b53b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 7f022867ec9f0166a0b4400385bb601b1c6b2c75b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 72eaef1f37a3b6bec11c342736834dc3707be3e4b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 491e33144dee872cffda207f6fcb09260728f803b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 8749946579708ea0d339034bb7f423a67dbe89cfb24df3e30cbf48255db866720fb71f14bf9d2f39 – before 96c436e4b010711452b2872558938f4ef276492ab24df3e30cbf48255db866720fb71f14bf9d2f39 – before 858d5ac22cb889266993e7670f9f0c4f4aeedd78b24df3e30cbf48255db866720fb71f14bf9d2f39 – before 05762c5bc1cfdcac36747994fde2c04387a457f1
Linux Linux 4.19

References