Heap-based buffer overflow in Linux kernel - CVE-2026-74556

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Main Vulnerability Database Vulnerabilities #VU143215

Heap-based buffer overflow in Linux kernel - CVE-2026-74556

Published: August 16, 2026


Vulnerability identifier: #VU143215
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-74556
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a heap-based buffer overflow in iscsi_tcp_hdr_dissect() in libiscsi_tcp when processing a crafted iSCSI SCSI Command Response pdu. A remote attacker can send a specially crafted response with an oversized data segment to cause a denial of service.

The issue occurs because sense or response data for ISCSI_OP_SCSI_CMD_RSP can exceed the fixed 8192-byte connection buffer while remaining within the negotiated maximum receive data segment length.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Micro
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux Server - AUS
SUSE Linux Enterprise Live Patching
Basesystem Module
Development Tools Module
Legacy Module
Public Cloud Module
openSUSE Leap
Ubuntu
kgraft-patch-4_12_14-122_328-default
kernel-livepatch-5_14_21-150400_24_240-default-debuginfo
kernel-livepatch-5_14_21-150400_24_240-default
kernel-livepatch-SLE15-SP4_Update_59-debugsource
kernel-livepatch-6_4_0-150600_23_135-default
kernel-livepatch-6_4_0-150600_23_135-default-debuginfo
kernel-livepatch-SLE15-SP6_Update_31-debugsource
kernel-livepatch-6_4_0-150700_53_81-default
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-default
kernel-default-debugsource
kernel-default-kgraft-devel
kernel-default-debuginfo
kernel-default-kgraft
dlm-kmp-default-debuginfo
kernel-syms
cluster-md-kmp-default-debuginfo
kernel-default-base-debuginfo
kernel-default-man
kernel-macros
kernel-devel
kernel-source
kernel-default-devel-debuginfo
kernel-default-base
kernel-default-devel
cluster-md-kmp-default
gfs2-kmp-default
ocfs2-kmp-default-debuginfo
gfs2-kmp-default-debuginfo
dlm-kmp-default
ocfs2-kmp-default
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-source-rt
kernel-rt-debugsource
kernel-rt-debuginfo
kernel-rt
kernel-obs-build
kernel-docs
kernel-obs-build-debugsource
kernel-64kb-debugsource
kernel-64kb
reiserfs-kmp-default
reiserfs-kmp-default-debuginfo
kernel-64kb-devel-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
kernel-zfcpdump
kernel-default-livepatch-devel
kernel-default-livepatch
kernel-64kb-devel
kernel-64kb-debuginfo
kernel-default-vdso
kernel-kvmsmall-vdso
kernel-debug-vdso-debuginfo
kernel-kvmsmall-vdso-debuginfo
kernel-debug-debuginfo
kernel-debug-devel
kernel-debug-debugsource
kernel-debug-devel-debuginfo
kernel-debug
kernel-default-extra-debuginfo
kernel-obs-qa
kernel-default-vdso-debuginfo
kernel-debug-vdso
kernel-kvmsmall-devel
kernel-kvmsmall-debugsource
kernel-kvmsmall-devel-debuginfo
kernel-kvmsmall-debuginfo
kernel-docs-html
kernel-source-vanilla
kernel-kvmsmall
kernel-default-optional-debuginfo
reiserfs-kmp-64kb
cluster-md-kmp-64kb-debuginfo
kselftests-kmp-default-debuginfo
kernel-default-extra
kernel-default-optional
kselftests-kmp-default
kernel-64kb-optional
gfs2-kmp-64kb-debuginfo
kernel-64kb-optional-debuginfo
cluster-md-kmp-64kb
kselftests-kmp-64kb
ocfs2-kmp-64kb
kernel-64kb-extra-debuginfo
kernel-64kb-extra
reiserfs-kmp-64kb-debuginfo
dlm-kmp-64kb
ocfs2-kmp-64kb-debuginfo
dlm-kmp-64kb-debuginfo
kselftests-kmp-64kb-debuginfo
gfs2-kmp-64kb
kernel-default-base-rebuild
kernel-azure
kernel-azure-devel
kernel-azure-debugsource
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
linux-nvidia-tegra (Ubuntu package)
linux (Debian package)

How to mitigate CVE-2026-74556

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kgraft-patch-4_12_14-122_328-default - update to 1-8.5.1
kernel-livepatch-5_14_21-150400_24_240-default-debuginfo - update to 1-150400.9.5.1
kernel-livepatch-5_14_21-150400_24_240-default - update to 1-150400.9.5.1
kernel-livepatch-SLE15-SP4_Update_59-debugsource - update to 1-150400.9.5.1
kernel-livepatch-6_4_0-150600_23_135-default - update to 1-150600.13.3.4
kernel-livepatch-6_4_0-150600_23_135-default-debuginfo - update to 1-150600.13.3.4
kernel-livepatch-SLE15-SP6_Update_31-debugsource - update to 1-150600.13.3.4
kernel-livepatch-6_4_0-150700_53_81-default - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_21-debugsource - 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-default - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-kgraft-devel - update to 4.12.14-122.328.1
kernel-default-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-kgraft - update to 4.12.14-122.328.1
dlm-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-syms - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-base-debuginfo - update to 4.12.14-122.328.1
kernel-default-man - update to 4.12.14-122.328.1
kernel-macros - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-devel - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-source - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-base - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2.150400.24.120.2, 6.4.0-150600.23.135.1.150600.12.62.4, 6.4.0-150700.53.81.1.150700.17.45.1
kernel-default-devel - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
cluster-md-kmp-default - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
gfs2-kmp-default - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
ocfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
gfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
dlm-kmp-default - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
ocfs2-kmp-default - addressed in versions 4.12.14-122.328.1, 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel (Red Hat package) - addressed in versions 4.18.0-305.211.1.el8_4, 4.18.0-372.220.1.el8_6, 4.18.0-553.163.1.el8_10, 5.14.0-687.48.1.el9_8, 6.12.0-211.55.1.el10_2
kernel-rt (Red Hat package) - update to 4.18.0-553.163.1.rt7.504.el8_10
kernel-source-rt - update to 5.14.21-150400.15.186.1
kernel-rt-debugsource - update to 5.14.21-150400.15.186.1
kernel-rt-debuginfo - update to 5.14.21-150400.15.186.1
kernel-rt - update to 5.14.21-150400.15.186.1
kernel-obs-build - addressed in versions 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-docs - addressed in versions 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-obs-build-debugsource - addressed in versions 5.14.21-150400.24.240.1, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-64kb-debugsource - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-64kb - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
reiserfs-kmp-default - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
reiserfs-kmp-default-debuginfo - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-zfcpdump-debugsource - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-zfcpdump-debuginfo - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-zfcpdump - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-livepatch - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-64kb-devel - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-64kb-debuginfo - addressed in versions 5.14.21-150400.24.240.2, 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-vdso - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-vdso - update to 6.4.0-150600.23.135.1
kernel-debug-vdso-debuginfo - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-vdso-debuginfo - update to 6.4.0-150600.23.135.1
kernel-debug-debuginfo - update to 6.4.0-150600.23.135.1
kernel-debug-devel - update to 6.4.0-150600.23.135.1
kernel-debug-debugsource - update to 6.4.0-150600.23.135.1
kernel-debug-devel-debuginfo - update to 6.4.0-150600.23.135.1
kernel-debug - update to 6.4.0-150600.23.135.1
kernel-default-extra-debuginfo - addressed in versions 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-obs-qa - update to 6.4.0-150600.23.135.1
kernel-default-vdso-debuginfo - update to 6.4.0-150600.23.135.1
kernel-debug-vdso - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-devel - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-debugsource - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-devel-debuginfo - update to 6.4.0-150600.23.135.1
kernel-kvmsmall-debuginfo - update to 6.4.0-150600.23.135.1
kernel-docs-html - update to 6.4.0-150600.23.135.1
kernel-source-vanilla - update to 6.4.0-150600.23.135.1
kernel-kvmsmall - update to 6.4.0-150600.23.135.1
kernel-default-optional-debuginfo - update to 6.4.0-150600.23.135.1
reiserfs-kmp-64kb - update to 6.4.0-150600.23.135.1
cluster-md-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
kselftests-kmp-default-debuginfo - update to 6.4.0-150600.23.135.1
kernel-default-extra - addressed in versions 6.4.0-150600.23.135.1, 6.4.0-150700.53.81.1
kernel-default-optional - update to 6.4.0-150600.23.135.1
kselftests-kmp-default - update to 6.4.0-150600.23.135.1
kernel-64kb-optional - update to 6.4.0-150600.23.135.1
gfs2-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
kernel-64kb-optional-debuginfo - update to 6.4.0-150600.23.135.1
cluster-md-kmp-64kb - update to 6.4.0-150600.23.135.1
kselftests-kmp-64kb - update to 6.4.0-150600.23.135.1
ocfs2-kmp-64kb - update to 6.4.0-150600.23.135.1
kernel-64kb-extra-debuginfo - update to 6.4.0-150600.23.135.1
kernel-64kb-extra - update to 6.4.0-150600.23.135.1
reiserfs-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
dlm-kmp-64kb - update to 6.4.0-150600.23.135.1
ocfs2-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
dlm-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
kselftests-kmp-64kb-debuginfo - update to 6.4.0-150600.23.135.1
gfs2-kmp-64kb - update to 6.4.0-150600.23.135.1
kernel-default-base-rebuild - update to 6.4.0-150600.23.135.1.150600.12.62.4
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
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
linux (Debian package) - update to 6.12.105-1

External References

Related Security Bulletins