Log in Start free

Vulnerability · Published May 6, 2026 · Assigned by Linux

CVE-2026-43185ksmbd: fix signededness bug in smb_direct_prepare_negotiation()

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 0.9% (higher than 59% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.9%top 40.5% 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: fix signededness bug in smb_direct_prepare_negotiation() smb_direct_prepare_negotiation() casts an unsigned __u32 value from sp->max_recv_size and req->preferred_send_size to a signed int before computing min_t(int, ...). A maliciously provided preferred_send_size of 0x80000000 will return as smaller than max_recv_size, and then be used to set the maximum allowed alowed receive size for the next message. By sending a second message with a large value (>1420 bytes) the attacker can then achieve a heap buffer overflow. This fix replaces min_t(int, ...) with min_t(u32)

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2026-43185
Debian:13linux6.12.115-2DEBIAN-CVE-2026-43185
Debian:14linux6.19.6-1DEBIAN-CVE-2026-43185
Ubuntu:22.04:LTSlinux5.15.0-185.195UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux6.8.0-134.134UBUNTU-CVE-2026-43185
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-aws5.15.0-1111.118UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-aws6.8.0-1060.63UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1060.63~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure5.15.0-1116.125UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-6.176.17.0-1021.21~24.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1116.125UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gcp5.15.0-1111.121UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gcp6.8.0-1063.69UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1020.22~24.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1063.69~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gke5.15.0-1107.113UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gke6.8.0-1058.64UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1094.102UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1045.48UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-hwe-6.176.17.0-40.40~24.04.1UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-hwe-6.176.17.0-40.40~24.04.1USN-8545-1
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-ibm5.15.0-1105.109UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-ibm6.8.0-1060.61UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1060.61~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1106.112UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-kvm5.15.0-1103.108UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-183.193UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-134.134.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-134.134.1~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1106.107UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1058.61UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1026.26UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1058.61.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1063.63UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1029.30UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1052.52UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1028.28UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oracle5.15.0-1108.114UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oracle6.8.0-1057.58UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1018.18~24.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1057.58~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-raspi5.15.0-1105.108UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-raspi6.8.0-1060.64UBUNTU-CVE-2026-43185
Ubuntu:25.10linux-raspi6.17.0-1021.21USN-8546-1
Ubuntu:25.10linux-raspi6.17.0-1021.21UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43185
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-134.134~22.04.1UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-43185
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1032.33UBUNTU-CVE-2026-43185
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1074.78UBUNTU-CVE-2026-43185

Affected products (as reported)

VendorProductVersions
Linux Linux 0626e6641f6b467447c81dd7678a69c66f7746cf – before 1c268fd2f59dc9ccb2c2a7d1f439b232dbe1c06c0626e6641f6b467447c81dd7678a69c66f7746cf – before 56eab82fa6fb5ca024b0514e249d40d9b23ee5a70626e6641f6b467447c81dd7678a69c66f7746cf – before a110dbe928561d440e9e117d17331139a0bedace0626e6641f6b467447c81dd7678a69c66f7746cf – before ceae058eb707ddd0d68f0872f9d9f23b7c30c37b0626e6641f6b467447c81dd7678a69c66f7746cf – before 55abc475d096da4a5356b6efb0cfdc6156bc15500626e6641f6b467447c81dd7678a69c66f7746cf – before 6b4f875aac344cdd52a1f34cc70ed2f874a65757
Linux Linux 5.15

References