ID

VAR-202107-1361

CVE

CVE-2021-33909

TITLE

Red Hat Security Advisory 2021-2732-01

DESCRIPTION

fs/seq_file.c in the Linux kernel 3.16 through 5.13.x before 5.13.4 does not properly restrict seq buffer allocations, leading to an integer overflow, an Out-of-bounds Write, and escalation to root by an unprivileged user, aka CID-8cae8cd89f05. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ==================================================================== Red Hat Security Advisory Synopsis: Important: kernel security update Advisory ID: RHSA-2021:2732-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2021:2732 Issue date: 2021-07-20 CVE Names: CVE-2020-28374 CVE-2021-3347 CVE-2021-33034 CVE-2021-33909 ==================================================================== 1. Summary: An update for kernel is now available for Red Hat Enterprise Linux 7.4 Advanced Update Support, Red Hat Enterprise Linux 7.4 Telco Extended Update Support, and Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. 2. Relevant releases/architectures: Red Hat Enterprise Linux Server AUS (v. 7.4) - noarch, x86_64 Red Hat Enterprise Linux Server E4S (v. 7.4) - noarch, ppc64le, x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 7.4) - x86_64 Red Hat Enterprise Linux Server Optional E4S (v. 7.4) - ppc64le, x86_64 Red Hat Enterprise Linux Server Optional TUS (v. 7.4) - x86_64 Red Hat Enterprise Linux Server TUS (v. 7.4) - noarch, x86_64 3. Description: The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: size_t-to-int conversion vulnerability in the filesystem layer (CVE-2021-33909) * kernel: SCSI target (LIO) write to any block on ILO backstore (CVE-2020-28374) * kernel: Use after free via PI futex state (CVE-2021-3347) * kernel: use-after-free in net/bluetooth/hci_event.c when destroying an hci_chan (CVE-2021-33034) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. 4. Solution: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. 5. Bugs fixed (https://bugzilla.redhat.com/): 1899804 - CVE-2020-28374 kernel: SCSI target (LIO) write to any block on ILO backstore 1922249 - CVE-2021-3347 kernel: Use after free via PI futex state 1961305 - CVE-2021-33034 kernel: use-after-free in net/bluetooth/hci_event.c when destroying an hci_chan 1970273 - CVE-2021-33909 kernel: size_t-to-int conversion vulnerability in the filesystem layer 6. Package List: Red Hat Enterprise Linux Server AUS (v. 7.4): Source: kernel-3.10.0-693.90.2.el7.src.rpm noarch: kernel-abi-whitelists-3.10.0-693.90.2.el7.noarch.rpm kernel-doc-3.10.0-693.90.2.el7.noarch.rpm x86_64: kernel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-headers-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-3.10.0-693.90.2.el7.x86_64.rpm perf-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm Red Hat Enterprise Linux Server E4S (v. 7.4): Source: kernel-3.10.0-693.90.2.el7.src.rpm noarch: kernel-abi-whitelists-3.10.0-693.90.2.el7.noarch.rpm kernel-doc-3.10.0-693.90.2.el7.noarch.rpm ppc64le: kernel-3.10.0-693.90.2.el7.ppc64le.rpm kernel-bootwrapper-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debug-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debug-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debuginfo-common-ppc64le-3.10.0-693.90.2.el7.ppc64le.rpm kernel-devel-3.10.0-693.90.2.el7.ppc64le.rpm kernel-headers-3.10.0-693.90.2.el7.ppc64le.rpm kernel-tools-3.10.0-693.90.2.el7.ppc64le.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-tools-libs-3.10.0-693.90.2.el7.ppc64le.rpm perf-3.10.0-693.90.2.el7.ppc64le.rpm perf-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm python-perf-3.10.0-693.90.2.el7.ppc64le.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm x86_64: kernel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-headers-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-3.10.0-693.90.2.el7.x86_64.rpm perf-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm Red Hat Enterprise Linux Server TUS (v. 7.4): Source: kernel-3.10.0-693.90.2.el7.src.rpm noarch: kernel-abi-whitelists-3.10.0-693.90.2.el7.noarch.rpm kernel-doc-3.10.0-693.90.2.el7.noarch.rpm x86_64: kernel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debug-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-devel-3.10.0-693.90.2.el7.x86_64.rpm kernel-headers-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-3.10.0-693.90.2.el7.x86_64.rpm perf-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm Red Hat Enterprise Linux Server Optional AUS (v. 7.4): x86_64: kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-devel-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm Red Hat Enterprise Linux Server Optional E4S (v. 7.4): ppc64le: kernel-debug-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debug-devel-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-debuginfo-common-ppc64le-3.10.0-693.90.2.el7.ppc64le.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm kernel-tools-libs-devel-3.10.0-693.90.2.el7.ppc64le.rpm perf-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.ppc64le.rpm x86_64: kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-devel-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm Red Hat Enterprise Linux Server Optional TUS (v. 7.4): x86_64: kernel-debug-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm kernel-tools-libs-devel-3.10.0-693.90.2.el7.x86_64.rpm perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm python-perf-debuginfo-3.10.0-693.90.2.el7.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2020-28374 https://access.redhat.com/security/cve/CVE-2021-3347 https://access.redhat.com/security/cve/CVE-2021-33034 https://access.redhat.com/security/cve/CVE-2021-33909 https://access.redhat.com/security/updates/classification/#important https://access.redhat.com/security/vulnerabilities/RHSB-2021-006 8. Contact: The Red Hat security contact is <secalert@redhat.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2021 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUBYPc9TtzjgjWX9erEAQj74Q/+MYfqRjICnJdQu26bEvEI/DN5Jt6YNmyM 8nVqaOD0vMaTmdK45RrH7PtEO/S/pm8/jnsDVrGwzSlyTnd6u/MHWOTlqvZvccn0 RBZ2CT2hMAtFjVZxnbKEXoaQW1eM0LFjjyTFTCcp32LydxcZMpXxmn162mCjhVje CtdLcO83TKFwQSE2n4h/DXS1Q11IOayaorc7W6y9V/d9ICEYl0L8hG46Zhui7T18 ylFKrvEwaPO1ZXDJajXlQRGoRgAbtUh1JD40u+R7XGM8dew+dk9hjV8FfdbKY1qv +SUBWlvPUahF3ZHsGFSIUO8442tijsUT3q4WY5xDkWDX4e1iQkLV0xPP2909xA5A noKv+jYhhkOnc7IrTUZDUhnu7qVl5oFhsXqmnHrhSb8/ntDfqwbKIknRmw4NEnIT hrvrSH3jR+gxlPGm7G4pnSujZ3H6pA14z7y6Dwv6BJg4IKkOvTO7SmmYZng9Jm5s efyzvRO3dBaoeFTcIaswmrxgWiCjs5lmj4SWl005uwuMSaeVvYG3EP1/mgDDgh0S PcnBoQqLot7C8U7QJquxUQ/PrxoAOcRcFCxbGG3MaAKq0xda1Rh/cAQhMsgBgQSq uBs6cFVvoQ5ObbGuiHGME39S2Va3T3c6Z3zz6QlBFPkaoxQHDrg5R3eJ8FMuW42m eDqZcy0vJHI=DoiN -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://listman.redhat.com/mailman/listinfo/rhsa-announce . Bug Fix(es): * [CKI kernel builds]: x86 binaries in non-x86 kernel rpms breaks systemtap [7.9.z] (BZ#1975159) 4. 8.2) - aarch64, noarch, ppc64le, s390x, x86_64 3. Bug Fix(es): * RHEL8.2 Snapshot2 - tpm: ibmvtpm: Wait for buffer to be set before proceeding (BZ#1933986) * fnic crash from invalid request pointer (BZ#1961707) * [Azure][RHEL8.4] Two Patches Needed To Enable Azure Host Time-syncing in VMs (BZ#1963051) * RHEL kernel 8.2 and higher are affected by data corruption bug in raid1 arrays using bitmaps. (BZ#1969338) 4. 7) - ppc64le, x86_64 3. Description: This is a kernel live patch module which is automatically loaded by the RPM post-install script to modify the code of a running kernel. ========================================================================= Ubuntu Security Notice USN-5015-1 July 20, 2021 linux-oem-5.10 vulnerabilities ========================================================================= A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS Summary: Several security issues were fixed in the Linux kernel. Software Description: - linux-oem-5.10: Linux kernel for OEM systems Details: It was discovered that the virtual file system implementation in the Linux kernel contained an unsigned to signed integer conversion error. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-33909) Michael Brown discovered that the Xen netback driver in the Linux kernel did not properly handle malformed packets from a network PV frontend, leading to a use-after-free vulnerability. An attacker in a guest VM could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2021-28691) It was discovered that the bluetooth subsystem in the Linux kernel did not properly handle HCI device initialization failure, leading to a double-free vulnerability. An attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2021-3564) It was discovered that the bluetooth subsystem in the Linux kernel did not properly handle HCI device detach events, leading to a use-after-free vulnerability. An attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2021-3573) It was discovered that the NFC implementation in the Linux kernel did not properly handle failed connect events leading to a NULL pointer dereference. A local attacker could use this to cause a denial of service. (CVE-2021-3587) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS: linux-image-5.10.0-1038-oem 5.10.0-1038.40 linux-image-oem-20.04 5.10.0.1038.40 linux-image-oem-20.04b 5.10.0.1038.40 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. (CVE-2021-33909) Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the nfc implementation in the Linux kernel. (CVE-2021-33034) It was discovered that an out-of-bounds (OOB) memory access flaw existed in the f2fs module of the Linux kernel. These packages include redhat-release-virtualization-host. RHVH features a Cockpit user interface for monitoring the host's resources and performing administrative tasks

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

local

TYPE

arbitrary

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Red Hat

SOURCES

LAST UPDATE DATE

2026-02-06T20:43:37.516000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE