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MEDIUM

CVE-2021-27363

CVSS v3

4.4

MEDIUM

EPSS Score

0.7 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • kernel-abi-whitelistsAlmaLinux:8all versions · fixed in 4.18.0-240.22.1.el8_3and 1 other package

Vendor advisories

  • CVE-2021-27363 Red Hat Product Security978 products fixed · 30 known affected

    kernel: iscsi: unrestricted access to sessions and handles

    kernel as a component of Red Hat Enterprise Linux 6 · kernel-abi-whitelists as a component of Red Hat Enterprise Linux 6 · kernel-bootwrapper as a component of Red Hat Enterprise Linux 6

  • RHSA-2021:1531 Red Hat Product Security120 products fixed

    Red Hat Security Advisory: kernel security and bug fix update

  • RHSA-2021:1376 Red Hat Product Security111 products fixed

    Red Hat Security Advisory: kernel security and bug fix update

  • RHSA-2021:1373 Red Hat Product Security24 products fixed

    Red Hat Security Advisory: kernel security and bug fix update

  • RHSA-2021:1289 Red Hat Product Security24 products fixed

    Red Hat Security Advisory: kernel security and bug fix update

  • RHSA-2021:1272 Red Hat Product Security120 products fixed

    Red Hat Security Advisory: kernel security, bug fix, and enhancement update

7 more advisories

Full record on NVD

Description

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.

Technical details

Published
2021-03-07

Frequently asked questions

What is CVE-2021-27363?

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.

Is CVE-2021-27363 actively exploited?

Active exploitation of CVE-2021-27363 has not been confirmed. Its EPSS score was 0.7% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-27363?

CVE-2021-27363 has a CVSS v3 base score of 4.4 (MEDIUM severity).

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