Integer underflow in Linux kernel - CVE-2026-64102

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Main Vulnerability Database Vulnerabilities #VU138534

Integer underflow in Linux kernel - CVE-2026-64102

Published: July 20, 2026


Vulnerability identifier: #VU138534
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64102
CWE-ID: CWE-191
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to cause a denial of service and disclose kernel memory contents.

The vulnerability exists due to an integer underflow in the Soft-iWARP receive path (siw_get_hdr/siw_tcp_rx_data) when processing a malformed iWARP FPDU with an MPA length smaller than the fixed header length for the opcode. A remote user can send a specially crafted FPDU to cause a denial of service and disclose kernel memory contents.

The issue is triggered by a malicious connected siw peer, and the negative signed length is later promoted to size_t during skb_copy_bits processing.


Affected software

Linux kernel
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Micro
SUSE Linux Micro Extras
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
Legacy Module
Development Tools Module
SUSE Linux Enterprise Live Patching
Basesystem Module
SUSE Real Time Module
Public Cloud Module
Ubuntu
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo
kernel-livepatch-6_4_0-150700_7_75-rt
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource
kernel-livepatch-6_4_0-150700_53_81-default
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-rt-livepatch
kernel-default
kernel-64kb
kernel-64kb-debugsource
kernel-64kb-devel
kernel-obs-build
kernel-syms
kernel-default-devel
kernel-default-debugsource
kernel-obs-build-debugsource
kernel-rt-debugsource
kernel-rt-debuginfo
kernel-rt
kernel-devel-rt
kernel-source-rt
kernel-kvmsmall
kernel-devel
kernel-macros
kernel-source
kernel-default-livepatch
kernel-default-debuginfo
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-default-devel-debuginfo
kernel-default-base
kernel-rt-devel
ocfs2-kmp-rt
gfs2-kmp-rt-debuginfo
dlm-kmp-rt
cluster-md-kmp-rt-debuginfo
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
ocfs2-kmp-rt-debuginfo
kernel-syms-rt
kernel-rt-devel-debuginfo
cluster-md-kmp-rt
kernel-docs
kernel-64kb-devel-debuginfo
kernel-64kb-debuginfo
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump
reiserfs-kmp-default
reiserfs-kmp-default-debuginfo
kernel-default-livepatch-devel
kernel-azure
kernel-azure-devel
kernel-azure-debugsource
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
kernel-default-extra-debuginfo
kernel-default-extra
cluster-md-kmp-default-debuginfo
dlm-kmp-default
gfs2-kmp-default-debuginfo
ocfs2-kmp-default
dlm-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
cluster-md-kmp-default
gfs2-kmp-default
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-raspi (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-gcp-6.8 (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-azure-6.8 (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-64102

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_75-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_81-default - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_21-debugsource - update to 1-150700.15.3.1
kernel (Red Hat package) - addressed in versions 4.18.0-553.170.1.el8_10, 5.14.0-687.53.1.el9_8
kernel-rt (Red Hat package) - update to 4.18.0-553.170.1.rt7.511.el8_10
kernel-rt-livepatch - update to 6.4.0-52.1
kernel-default - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-64kb - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-64kb-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-64kb-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-obs-build - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-syms - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-rt-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-rt-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-devel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-source-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-kvmsmall - update to 6.4.0-52.1
kernel-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-macros - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-source - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-livepatch - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall-debugsource - update to 6.4.0-52.1
kernel-kvmsmall-debuginfo - update to 6.4.0-52.1
kernel-default-devel-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-base - addressed in versions 6.4.0-52.1.21.35, 6.4.0-52.1.21.36, 6.4.0-150700.53.81.1.150700.17.45.1
kernel-rt-devel - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
dlm-kmp-rt - update to 6.4.0-150700.7.75.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
kernel-syms-rt - update to 6.4.0-150700.7.75.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.75.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.75.1
kernel-docs - update to 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.81.1
kernel-azure - update to 6.4.0-150700.53.81.1
kernel-azure-devel - update to 6.4.0-150700.53.81.1
kernel-azure-debugsource - update to 6.4.0-150700.53.81.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
dlm-kmp-default - update to 6.4.0-150700.53.81.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default - update to 6.4.0-150700.53.81.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default - update to 6.4.0-150700.53.81.1
gfs2-kmp-default - update to 6.4.0-150700.53.81.1
linux (Ubuntu package) - addressed in versions 5.15.0-184.194~20.04.1, 5.15.0-184.194, 5.15.0-186.196~20.04.1, 5.15.0-186.196, 5.15.0-1075.79, 5.15.0-1095.103, 5.15.0-1104.109, 5.15.0-1108.114, 5.15.0-1111.120+fips1, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 5.15.0.184.155, 5.15.0.186.166, 5.15.0.1075.78, 5.15.0.1095.94, 5.15.0.1104.100, 5.15.0.1108.107, 5.15.0.1111.115, 5.15.0.1112.102, 5.15.0.1112.109, 6.8.0-139.139+fips1, 6.8.0-1049.53, 6.8.0-1062.65~22.04.1, 6.8.0-1062.65+fips1, 6.8.0-1062.65.1, 6.8.0-1062.70, 6.8.0-1064.68, 6.8.0-1067.75, 6.8.0-1067.75+fips1, 6.8.1-1059.60~22.04.1, 6.8.1-1059.60
linux-aws (Ubuntu package) - addressed in versions 5.15.0-186.196+fips1, 5.15.0-1106.110, 5.15.0-1107.108, 5.15.0-1112.119~20.04.1, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0.186.109, 5.15.0.1106.103, 5.15.0.1107.107, 5.15.0.1112.108, 5.15.0.1112.115, 6.8.0-1064.67~22.04.1, 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0-1064.66, 5.15.0.1053.55, 5.15.0.1064.64, 6.8.0-1035.38
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0-1107.113~20.04.1, 5.15.0.1104.108
linux-raspi (Ubuntu package) - addressed in versions 5.15.0-1106.109, 5.15.0.1106.104
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0-1107.113, 5.15.0.1107.106
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-azure (Ubuntu package) - addressed in versions 5.15.0-1109.115, 5.15.0-1117.126, 5.15.0.1109.105, 5.15.0.1117.115, 6.8.0-1067.75, 7.0.0-1009.9, 7.0.0-1010.10
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1112.122~20.04.1
linux-azure-fde (Ubuntu package) - update to 5.15.0-1117.126
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0-1117.126+fips1, 5.15.0.1117.102, 6.8.0-1067.75+fips1
linux-lowlatency (Ubuntu package) - addressed in versions 6.8.0-139.139.1~22.04.1, 6.8.0-139.139.1
linux-gcp-6.8 (Ubuntu package) - addressed in versions 6.8.0-1036.37, 6.8.0-1064.65, 6.8.0-1067.75~22.04.1
linux-oracle (Ubuntu package) - addressed in versions 6.8.0-1061.64~22.04.1, 6.8.0-1061.64
linux-aws-fips (Ubuntu package) - update to 6.8.0-1064.67+fips1
linux-azure-6.8 (Ubuntu package) - update to 6.8.0-1067.75~22.04.1
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2053.55
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

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