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medium 4.4

CVE-2021-27363 json

An issue was discovered in the Linux kernel through 5.11.3.

published 5y ago modified 4mo ago also EUVD-2021-14122

cvss
4.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

An issue was discovered in the Linux kernel through 5.11.3. A kernel pointer leak can be used to determine the address of the iscsi_transport structure. When an iSCSI transport is registered with the iSCSI subsystem, the transport's handle is available to unprivileged users via the sysfs file system, at /sys/class/iscsi_transport/$TRANSPORT_NAME/handle. When read, the show_transport_handle function (in drivers/scsi/scsi_transport_iscsi.c) is called, which leaks the handle. This handle is actually the pointer to an iscsi_transport struct in the kernel module's global variables.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.10.24-1

debian advisories DEBIAN-CVE-2021-27363

  • linux Ubuntu 16.04 LTS 4.4.0-206.238
  • linux Ubuntu 18.04 LTS 4.15.0-139.143
  • linux Ubuntu 20.04 LTS 5.4.0-70.78
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1124.138
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1096.103
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1041.43
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1095.108~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1040.43

ubuntu advisories UBUNTU-CVE-2021-27363

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 RHEL 8 4.18.0-240.22.1.el8_3
  • perf RHEL 8 4.18.0-240.22.1.el8_3
  • bpftool RHEL 8 4.18.0-240.22.1.el8_3
  • kernel-core RHEL 8 4.18.0-240.22.1.el8_3
  • kernel-tools RHEL 8 4.18.0-240.22.1.el8_3
  • python3-perf RHEL 8 4.18.0-240.22.1.el8_3
  • kernel-modules RHEL 8 4.18.0-240.22.1.el8_3
  • kernel-zfcpdump RHEL 8 4.18.0-240.22.1.el8_3

red hat advisories RHSA-2021:1093RHSA-2021:1081RHSA-2021:1267RHSA-2021:1531RHSA-2021:1279RHSA-2021:1272

  • kernel-64kb SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-syms SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-source SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-default SLE Workstation Extension 15 SP3, SLE Module for Legacy 15 SP3, SLE Module for Basesystem 15 SP3 +2 more 5.3.18-59.5.2
  • kernel-preempt SLE Workstation Extension 15 SP3, SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-zfcpdump SLE Module for Basesystem 15 SP3 5.3.18-59.5.2
  • kernel-obs-build SLE Module for Development Tools 15 SP3 5.3.18-59.5.1
  • kernel-default-base SLE Module for Basesystem 15 SP3 5.3.18-59.5.2.18.2.2

suse advisories SUSE-SU-2021:2577-1SUSE-SU-2021:1977-1SUSE-SU-2021:1975-1SUSE-SU-2021:1625-1SUSE-SU-2021:1624-1SUSE-SU-2021:1623-1

  • kernel-64kb openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-syms openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-59.5.1
  • kernel-source openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-default openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-preempt openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-kvmsmall openSUSE Leap 15.3 5.3.18-59.5.2
  • kernel-zfcpdump openSUSE Leap 15.3 5.3.18-59.5.2

opensuse advisories openSUSE-SU-2021:1977-1openSUSE-SU-2021:1975-1openSUSE-SU-2021:0758-1openSUSE-SU-2021:0532-1

  • kernel-abi-whitelists AlmaLinux 8 4.18.0-240.22.1.el8_3

almalinux advisories ALSA-2021:1093

  • kernel CBL-Mariner 2.0 5.10.78.1-1

azure linux advisories AZL-6532

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

  • linux-hardened Arch Linux 5.10.21.hardened1-1
  • linux Arch Linux 5.11.4.arch1-1
  • linux-zen Arch Linux 5.11.4.zen1-1
  • linux-lts Arch Linux 5.10.21-1

arch linux advisories AVG-1645AVG-1651AVG-1653AVG-1655

Is CVE-2021-27363 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-27363 updated cvss 4.4

kernel: iscsi: unrestricted access to sessions and handles

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, kernel-alt, python-perf, kernel-kdump, kernel-tools, +3 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-240.22.1.el8_3, kernel-debuginfo-common-aarch64 4.18.0-240.22.1.el8_3, kernel-debuginfo-common-ppc64le 4.18.0-240.22.1.el8_3
    fixed: vendor fix RHSA-2021:1093
  • Red Hat CodeReady Linux Builder EUS (v. 8.1) kernel-debuginfo-common-x86_64 4.18.0-147.44.1.el8_1, kernel-debuginfo-common-aarch64 4.18.0-147.44.1.el8_1, kernel-debuginfo-common-ppc64le 4.18.0-147.44.1.el8_1
    fixed: vendor fix RHSA-2021:1171
  • Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-debuginfo-common-x86_64 4.18.0-193.51.1.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.51.1.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.51.1.el8_2
    fixed: vendor fix RHSA-2021:1272
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-240.22.1.el8_3, kernel 4.18.0-240.22.1.el8_3, bpftool 4.18.0-240.22.1.el8_3, kernel-core 4.18.0-240.22.1.el8_3, kernel-tools 4.18.0-240.22.1.el8_3, python3-perf 4.18.0-240.22.1.el8_3, +15 more
    fixed: vendor fix RHSA-2021:1093
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) perf 4.18.0-147.44.1.el8_1, kernel 4.18.0-147.44.1.el8_1, bpftool 4.18.0-147.44.1.el8_1, kernel-core 4.18.0-147.44.1.el8_1, kernel-tools 4.18.0-147.44.1.el8_1, python3-perf 4.18.0-147.44.1.el8_1, +15 more
    fixed: vendor fix RHSA-2021:1171
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) perf 4.18.0-193.51.1.el8_2, kernel 4.18.0-193.51.1.el8_2, bpftool 4.18.0-193.51.1.el8_2, kernel-core 4.18.0-193.51.1.el8_2, kernel-tools 4.18.0-193.51.1.el8_2, python3-perf 4.18.0-193.51.1.el8_2, +15 more
    fixed: vendor fix RHSA-2021:1272
  • Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-1160.24.1.el7, kernel 3.10.0-1160.24.1.el7, bpftool 3.10.0-1160.24.1.el7, python-perf 3.10.0-1160.24.1.el7, kernel-tools 3.10.0-1160.24.1.el7, kernel-tools-libs 3.10.0-1160.24.1.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.24.1.el7
    fixed: vendor fix RHSA-2021:1071
show 25 more
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.6) perf 3.10.0-957.72.1.el7, kernel 3.10.0-957.72.1.el7, bpftool 3.10.0-957.72.1.el7, python-perf 3.10.0-957.72.1.el7, kernel-tools 3.10.0-957.72.1.el7, kernel-tools-libs 3.10.0-957.72.1.el7, +2 more
    fixed: vendor fix RHSA-2021:1376
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.7) perf 3.10.0-1062.49.1.el7, kernel 3.10.0-1062.49.1.el7, bpftool 3.10.0-1062.49.1.el7, python-perf 3.10.0-1062.49.1.el7, kernel-tools 3.10.0-1062.49.1.el7, kernel-tools-libs 3.10.0-1062.49.1.el7, +2 more
    fixed: vendor fix RHSA-2021:1531
  • Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.24.1.el7
    fixed: vendor fix RHSA-2021:1071
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.6) kernel-debuginfo-common-x86_64 3.10.0-957.72.1.el7
    fixed: vendor fix RHSA-2021:1376
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.7) kernel-debuginfo-common-x86_64 3.10.0-1062.49.1.el7
    fixed: vendor fix RHSA-2021:1531
  • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-trace 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.24.1.rt56.1161.el7 Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-kvm 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-trace 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-debug-kvm 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-trace-kvm 3.10.0-1160.24.1.rt56.1161.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.24.1.rt56.1161.el7
    fixed: vendor fix RHSA-2021:1070
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-core 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-modules 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-debug-core 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-debug-modules 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-modules-extra 4.18.0-240.22.1.rt7.77.el8_3, +2 more
    fixed: vendor fix RHSA-2021:1081
  • Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-core 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-modules 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-debug-core 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-debug-modules 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-modules-extra 4.18.0-193.51.1.rt13.101.el8_2, +2 more
    fixed: vendor fix RHSA-2021:1279
  • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-kvm 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-core 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-modules 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-debug-kvm 4.18.0-240.22.1.rt7.77.el8_3, kernel-rt-debug-core 4.18.0-240.22.1.rt7.77.el8_3, +4 more
    fixed: vendor fix RHSA-2021:1081
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-kvm 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-core 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-modules 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-debug-kvm 4.18.0-193.51.1.rt13.101.el8_2, kernel-rt-debug-core 4.18.0-193.51.1.rt13.101.el8_2, +4 more
    fixed: vendor fix RHSA-2021:1279
  • Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-1160.24.1.el7, kernel 3.10.0-1160.24.1.el7, bpftool 3.10.0-1160.24.1.el7, python-perf 3.10.0-1160.24.1.el7, kernel-kdump 3.10.0-1160.24.1.el7, kernel-tools 3.10.0-1160.24.1.el7, +7 more
    fixed: vendor fix RHSA-2021:1071
  • Red Hat Enterprise Linux Server AUS (v. 7.2) perf 3.10.0-327.96.1.el7, kernel 3.10.0-327.96.1.el7, python-perf 3.10.0-327.96.1.el7, kernel-tools 3.10.0-327.96.1.el7, kernel-tools-libs 3.10.0-327.96.1.el7, kernel-abi-whitelists 3.10.0-327.96.1.el7, +1 more
    fixed: vendor fix RHSA-2021:1289
  • Red Hat Enterprise Linux Server AUS (v. 7.3) perf 3.10.0-514.88.1.el7, kernel 3.10.0-514.88.1.el7, python-perf 3.10.0-514.88.1.el7, kernel-tools 3.10.0-514.88.1.el7, kernel-tools-libs 3.10.0-514.88.1.el7, kernel-abi-whitelists 3.10.0-514.88.1.el7, +1 more
    fixed: vendor fix RHSA-2021:1373
  • Red Hat Enterprise Linux Server AUS (v. 7.4) perf 3.10.0-693.84.1.el7, kernel 3.10.0-693.84.1.el7, python-perf 3.10.0-693.84.1.el7, kernel-tools 3.10.0-693.84.1.el7, kernel-tools-libs 3.10.0-693.84.1.el7, kernel-abi-whitelists 3.10.0-693.84.1.el7, +1 more Red Hat Enterprise Linux Server E4S (v. 7.4) perf 3.10.0-693.84.1.el7, kernel 3.10.0-693.84.1.el7, python-perf 3.10.0-693.84.1.el7, kernel-tools 3.10.0-693.84.1.el7, kernel-tools-libs 3.10.0-693.84.1.el7, kernel-bootwrapper 3.10.0-693.84.1.el7, +3 more
    fixed: vendor fix RHSA-2021:1267
  • Red Hat Enterprise Linux Server EUS (v. 7.6) perf 3.10.0-957.72.1.el7, kernel 3.10.0-957.72.1.el7, bpftool 3.10.0-957.72.1.el7, python-perf 3.10.0-957.72.1.el7, kernel-kdump 3.10.0-957.72.1.el7, kernel-tools 3.10.0-957.72.1.el7, +7 more
    fixed: vendor fix RHSA-2021:1376
  • Red Hat Enterprise Linux Server EUS (v. 7.7) perf 3.10.0-1062.49.1.el7, kernel 3.10.0-1062.49.1.el7, bpftool 3.10.0-1062.49.1.el7, python-perf 3.10.0-1062.49.1.el7, kernel-kdump 3.10.0-1062.49.1.el7, kernel-tools 3.10.0-1062.49.1.el7, +7 more
    fixed: vendor fix RHSA-2021:1531
  • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-1160.24.1.el7, kernel-debuginfo-common-x86_64 3.10.0-1160.24.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1160.24.1.el7
    fixed: vendor fix RHSA-2021:1071
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.2) kernel-debuginfo-common-x86_64 3.10.0-327.96.1.el7
    fixed: vendor fix RHSA-2021:1289
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.3) kernel-debuginfo-common-x86_64 3.10.0-514.88.1.el7
    fixed: vendor fix RHSA-2021:1373
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.84.1.el7 Red Hat Enterprise Linux Server Optional E4S (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.84.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-693.84.1.el7
    fixed: vendor fix RHSA-2021:1267
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.6) kernel-debuginfo-common-ppc64 3.10.0-957.72.1.el7, kernel-debuginfo-common-x86_64 3.10.0-957.72.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-957.72.1.el7
    fixed: vendor fix RHSA-2021:1376
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.7) kernel-debuginfo-common-ppc64 3.10.0-1062.49.1.el7, kernel-debuginfo-common-x86_64 3.10.0-1062.49.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1062.49.1.el7
    fixed: vendor fix RHSA-2021:1531
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.84.1.el7 Red Hat Enterprise Linux Server TUS (v. 7.4) perf 3.10.0-693.84.1.el7, kernel 3.10.0-693.84.1.el7, python-perf 3.10.0-693.84.1.el7, kernel-tools 3.10.0-693.84.1.el7, kernel-tools-libs 3.10.0-693.84.1.el7, kernel-abi-whitelists 3.10.0-693.84.1.el7, +1 more
    fixed: vendor fix RHSA-2021:1267
  • Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-1160.24.1.el7, kernel 3.10.0-1160.24.1.el7, bpftool 3.10.0-1160.24.1.el7, python-perf 3.10.0-1160.24.1.el7, kernel-tools 3.10.0-1160.24.1.el7, kernel-tools-libs 3.10.0-1160.24.1.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.24.1.el7
    fixed: vendor fix RHSA-2021:1071
  • Red Hat Virtualization 4.2 Hypervisor for RHEL 7.6 EUS perf 3.10.0-957.72.1.el7, python-perf 3.10.0-957.72.1.el7
    fixed: vendor fix RHSA-2021:1376

1 more not affected in the full advisory

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

0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • blog.grimm-co.com https://blog.grimm-co.com/2021/03/new-old-bugs-in-linux-kernel.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 4.4 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
NVD 2.0 3.6 AV:L/AC:L/Au:N/C:P/I:N/A:P

Classification

Technology feeds

References

Sources

Fencer Intel 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.