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Fencer Vulns
critical 9.1

CVE-2026-90011 in the critical feed json

scsi: target: iscsi: Reserve a terminator byte for the login payload

published 2026-09-16 54 d ago modified 2026-10-19 21 d ago also EUVD-2026-80619

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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

scsi: target: iscsi: Reserve a terminator byte for the login payload

iscsi_target_check_login_request() rejects a login PDU whose DataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is '>' and login->req_buf is allocated with exactly MAX_KEY_VALUE_PAIRS bytes. Since iscsit_get_login_rx() receives payload_length + padding bytes, where

padding = ((-payload_length) & 3);

any payload_length from 8189 to 8192 fills the whole 8192 byte buffer. The write stays in bounds, but no byte is left for a NUL terminator.

The buffer is subsequently consumed as a C string. In the CHAP path chap_check_algorithm() calls kstrdup(a_str), and extract_param() calls strstr(in_buf, pattern) followed by strlen_semi(), none of which take a length. convert_null_to_semi() additionally rewrites every embedded NUL to ';', so even a payload made of well formed NUL separated key=value records is left without a terminator. These walk past the end of the object into adjacent slab memory. It is reachable by an unauthenticated initiator against a portal configured for CHAP; when authentication is not required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and the CHAP path is never entered.

Allocate one extra byte. kzalloc() zeroes it and nothing ever writes to it, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS bytes, so the buffer is always terminated.

Patch / fix

  • Linux Linux 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-90011

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-90011

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-rt SLE Micro 5.4 5.14.21-150400.15.192.2
  • kernel-source-rt SLE Micro 5.4 5.14.21-150400.15.192.2
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.167.2
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.167.2
  • kernel-64kb SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 5.14.21-150400.24.246.1

suse advisories SUSE-SU-2026:4940-1SUSE-SU-2026:4939-1SUSE-SU-2026:4938-1SUSE-SU-2026:4937-1SUSE-SU-2026:4936-1SUSE-SU-2026:4935-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.40.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.40.1

opensuse advisories openSUSE-SU-2026:22167-1openSUSE-SU-2026:11880-1

  • kernel-rt AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel AlmaLinux 8 4.18.0-553.180.1.el8_10

almalinux advisories ALSA-2026:92208ALSA-2026:92209

  • kernel Rocky Linux 10 6.12.0-211.72.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.64.1.el9_8
  • kernel Rocky Linux 8 4.18.0-553.180.1.el8_10.cloud.0.1
  • kernel-rt Rocky Linux 8 4.18.0-553.180.1.rt7.521.el8_10
  • kernel Rocky Linux 8 4.18.0-553.180.1.el8_10

rocky linux advisories RLSA-2026:93413RLSA-2026:93412RXSA-2026:92209RLSA-2026:92208RLSA-2026:92209

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-101213

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-90011 updated cvss 8.1

kernel: scsi: target: iscsi: Reserve a terminator byte for the login payload

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.64.1.el9_8, perf 5.14.0-687.64.1.el9_8, rtla 5.14.0-687.64.1.el9_8, python3-perf 5.14.0-687.64.1.el9_8, kernel-devel-matched 5.14.0-687.64.1.el9_8, kernel-64k-devel-matched 5.14.0-687.64.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.72.1.el10_2, perf 6.12.0-211.72.1.el10_2, rtla 6.12.0-211.72.1.el10_2, python3-perf 6.12.0-211.72.1.el10_2, kernel-devel-matched 6.12.0-211.72.1.el10_2, kernel-64k-devel-matched 6.12.0-211.72.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.180.1.el8_10, kernel 4.18.0-553.180.1.el8_10, bpftool 4.18.0-553.180.1.el8_10, kernel-core 4.18.0-553.180.1.el8_10, kernel-tools 4.18.0-553.180.1.el8_10, python3-perf 4.18.0-553.180.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:92209
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.64.1.el9_8, kernel-64k 5.14.0-687.64.1.el9_8, kernel-core 5.14.0-687.64.1.el9_8, kernel-tools 5.14.0-687.64.1.el9_8, kernel-modules 5.14.0-687.64.1.el9_8, kernel-64k-core 5.14.0-687.64.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.72.1.el10_2, kernel-64k 6.12.0-211.72.1.el10_2, kernel-core 6.12.0-211.72.1.el10_2, kernel-tools 6.12.0-211.72.1.el10_2, kernel-modules 6.12.0-211.72.1.el10_2, kernel-64k-core 6.12.0-211.72.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.64.1.el9_8
    fixed: vendor fix RHSA-2026:93412
show 11 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.180.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.180.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.180.1.el8_10
    fixed: vendor fix RHSA-2026:92209
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-kvm 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-core 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-modules 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-debug-kvm 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-debug-core 4.18.0-553.180.1.rt7.521.el8_10, +4 more
    fixed: vendor fix RHSA-2026:92208
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.64.1.el9_8, kernel-rt-64k 5.14.0-687.64.1.el9_8, kernel-rt-core 5.14.0-687.64.1.el9_8, kernel-rt-modules 5.14.0-687.64.1.el9_8, kernel-rt-64k-core 5.14.0-687.64.1.el9_8, kernel-rt-debug-core 5.14.0-687.64.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.72.1.el10_2, kernel-rt-64k 6.12.0-211.72.1.el10_2, kernel-rt-core 6.12.0-211.72.1.el10_2, kernel-rt-modules 6.12.0-211.72.1.el10_2, kernel-rt-64k-core 6.12.0-211.72.1.el10_2, kernel-rt-debug-core 6.12.0-211.72.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.64.1.el9_8, kernel-rt-core 5.14.0-687.64.1.el9_8, kernel-rt-modules 5.14.0-687.64.1.el9_8, kernel-rt-debug-core 5.14.0-687.64.1.el9_8, kernel-rt-modules-core 5.14.0-687.64.1.el9_8, kernel-rt-debug-modules 5.14.0-687.64.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.72.1.el10_2, kernel-rt-core 6.12.0-211.72.1.el10_2, kernel-rt-modules 6.12.0-211.72.1.el10_2, kernel-rt-debug-core 6.12.0-211.72.1.el10_2, kernel-rt-modules-core 6.12.0-211.72.1.el10_2, kernel-rt-debug-modules 6.12.0-211.72.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-core 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-modules 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-debug-core 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-debug-modules 4.18.0-553.180.1.rt7.521.el8_10, kernel-rt-modules-extra 4.18.0-553.180.1.rt7.521.el8_10, +2 more
    fixed: vendor fix RHSA-2026:92208
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202611032353
    fixed: vendor fix RHSA-2026:95346
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.