ID

VAR-202107-1361

CVE

CVE-2021-33909

TITLE

Linux kernel Input validation error vulnerability

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. CVE-2020-36311 A flaw was discovered in the KVM subsystem for AMD CPUs, allowing an attacker to cause a denial of service by triggering destruction of a large SEV VM. CVE-2021-3609 Norbert Slusarek reported a race condition vulnerability in the CAN BCM networking protocol, allowing a local attacker to escalate privileges. An unprivileged local attacker able to create, mount, and then delete a deep directory structure whose total path length exceeds 1GB, can take advantage of this flaw for privilege escalation. Details can be found in the Qualys advisory at https://www.qualys.com/2021/07/20/cve-2021-33909/sequoia-local-privilege-escalation-linux.txt CVE-2021-34693 Norbert Slusarek discovered an information leak in the CAN BCM networking protocol. A local attacker can take advantage of this flaw to obtain sensitive information from kernel stack memory. For the stable distribution (buster), these problems have been fixed in version 4.19.194-3. For the detailed security status of linux please refer to its security tracker page at: https://security-tracker.debian.org/tracker/linux Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: https://www.debian.org/security/ Mailing list: debian-security-announce@lists.debian.org -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEERkRAmAjBceBVMd3uBUy48xNDz0QFAmD2xvFfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDQ2 NDQ0MDk4MDhDMTcxRTA1NTMxRERFRTA1NENCOEYzMTM0M0NGNDQACgkQBUy48xND z0Tp/g//af2JkknfeqLs9FHFlqiYvIl1co4zEOW6e4BO8WAtvB3q5+scTNiFgN/W 66o9sDTi+Bnuhxja/lsZEkwM5QnrcPCSndUuY8EIOBDRdAla9R3xf4vUSYQ4KVb8 re3NmfzlkiLiGd6JRZXeV8+8stUjbLc6e0EG36S2HJ6hDs7pOA+vxcR/ui8yf15e p9egIKOqznhsNFHgrZRm4R1yqgNzfkFBWeSgfuFZGsFi9b2I3FJQKDTx0TXwxerB PKtvstJ1/xKbtK8m5IdntLOPeUPXuUlhoff4cN192IRNrPCcUXf7vRJoGg6A7WP2 dfvErldL8AsJHMBEs6YqEQSajFMoJX2590Bt8VK1xZwvhirSB7ZClk4+boh8OhlG apKj/OPIi3KGPt2s8t23zq3cU6aAFyTp6VQacuS+kR/2bdF0H3iQKcB5I4HFSSx9 BxK0ZpcZSw4axt35lfVhqnoeARb2GtUBqO77CWOOdtXcxDACD3VQ8PiqxxfpGS26 V/ASWmWzCeoGs+FQ5iRoN2JC5i9VcJX32r0fbNVvj7BG+ZQBe5XZ30eOalQLPs4/ SQnBoWuMnIpl/5+6FxkPXiqzkDGnkUm2ep2gXhdFrJmn/3ugpMiAPEuETo7Q2Lfj Ze6DKkHJPBK2BaKs1UgWPNvQBVQrcs0rKMLEf6LxS0eAJHlcCdo= =dhUe -----END PGP SIGNATURE----- . -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ==================================================================== Red Hat Security Advisory Synopsis: Important: kernel security update Advisory ID: RHSA-2021:2735-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2021:2735 Issue date: 2021-07-20 CVE Names: CVE-2020-12362 CVE-2021-3347 CVE-2021-33909 ==================================================================== 1. Summary: An update for kernel is now available for Red Hat Enterprise Linux 6 Extended Lifecycle Support. 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 (v. 6 ELS) - i386, noarch, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6 ELS) - i386, s390x, 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: Integer overflow in Intel(R) Graphics Drivers (CVE-2020-12362) * kernel: Use after free via PI futex state (CVE-2021-3347) 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/): 1922249 - CVE-2021-3347 kernel: Use after free via PI futex state 1930246 - CVE-2020-12362 kernel: Integer overflow in Intel(R) Graphics Drivers 1970273 - CVE-2021-33909 kernel: size_t-to-int conversion vulnerability in the filesystem layer 6. Package List: Red Hat Enterprise Linux Server (v. 6 ELS): Source: kernel-2.6.32-754.41.2.el6.src.rpm i386: kernel-2.6.32-754.41.2.el6.i686.rpm kernel-debug-2.6.32-754.41.2.el6.i686.rpm kernel-debug-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debug-devel-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-common-i686-2.6.32-754.41.2.el6.i686.rpm kernel-devel-2.6.32-754.41.2.el6.i686.rpm kernel-headers-2.6.32-754.41.2.el6.i686.rpm perf-2.6.32-754.41.2.el6.i686.rpm perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm noarch: kernel-abi-whitelists-2.6.32-754.41.2.el6.noarch.rpm kernel-doc-2.6.32-754.41.2.el6.noarch.rpm kernel-firmware-2.6.32-754.41.2.el6.noarch.rpm s390x: kernel-2.6.32-754.41.2.el6.s390x.rpm kernel-debug-2.6.32-754.41.2.el6.s390x.rpm kernel-debug-debuginfo-2.6.32-754.41.2.el6.s390x.rpm kernel-debug-devel-2.6.32-754.41.2.el6.s390x.rpm kernel-debuginfo-2.6.32-754.41.2.el6.s390x.rpm kernel-debuginfo-common-s390x-2.6.32-754.41.2.el6.s390x.rpm kernel-devel-2.6.32-754.41.2.el6.s390x.rpm kernel-headers-2.6.32-754.41.2.el6.s390x.rpm kernel-kdump-2.6.32-754.41.2.el6.s390x.rpm kernel-kdump-debuginfo-2.6.32-754.41.2.el6.s390x.rpm kernel-kdump-devel-2.6.32-754.41.2.el6.s390x.rpm perf-2.6.32-754.41.2.el6.s390x.rpm perf-debuginfo-2.6.32-754.41.2.el6.s390x.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.s390x.rpm x86_64: kernel-2.6.32-754.41.2.el6.x86_64.rpm kernel-debug-2.6.32-754.41.2.el6.x86_64.rpm kernel-debug-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debug-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm kernel-debug-devel-2.6.32-754.41.2.el6.i686.rpm kernel-debug-devel-2.6.32-754.41.2.el6.x86_64.rpm kernel-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm kernel-debuginfo-common-i686-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-common-x86_64-2.6.32-754.41.2.el6.x86_64.rpm kernel-devel-2.6.32-754.41.2.el6.x86_64.rpm kernel-headers-2.6.32-754.41.2.el6.x86_64.rpm perf-2.6.32-754.41.2.el6.x86_64.rpm perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm perf-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm Red Hat Enterprise Linux Server Optional (v. 6 ELS): i386: kernel-debug-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-2.6.32-754.41.2.el6.i686.rpm kernel-debuginfo-common-i686-2.6.32-754.41.2.el6.i686.rpm perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm python-perf-2.6.32-754.41.2.el6.i686.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.i686.rpm s390x: kernel-debug-debuginfo-2.6.32-754.41.2.el6.s390x.rpm kernel-debuginfo-2.6.32-754.41.2.el6.s390x.rpm kernel-debuginfo-common-s390x-2.6.32-754.41.2.el6.s390x.rpm kernel-kdump-debuginfo-2.6.32-754.41.2.el6.s390x.rpm perf-debuginfo-2.6.32-754.41.2.el6.s390x.rpm python-perf-2.6.32-754.41.2.el6.s390x.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.s390x.rpm x86_64: kernel-debug-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm kernel-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm kernel-debuginfo-common-x86_64-2.6.32-754.41.2.el6.x86_64.rpm perf-debuginfo-2.6.32-754.41.2.el6.x86_64.rpm python-perf-2.6.32-754.41.2.el6.x86_64.rpm python-perf-debuginfo-2.6.32-754.41.2.el6.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-2020-12362 https://access.redhat.com/security/cve/CVE-2021-3347 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 iQIVAwUBYPc4YtzjgjWX9erEAQgIaA//UYu+fLneuZ2zgqYYAam/u9hDvf3bHK+6 gXrL3MWGN58w+npoNVJZAJ25ooUhUbvIE+YjHeU/wJIts7ctHmRLkRudgulnM8dv G6xTdD1UB5Qywd83jOTGO8wFx0q1QpRABVFfjiIrDoa4O9dwacYVTKWkxHBQO4Z2 IKXLje41BXYI3WDHU81EgwdiDlTDPOwDh/JQMOSmHap9fz++WgsJjvdvqyYIS6tT OkUBydCD5S+ZZ5p0YDXQK5Z/sgnFne/0bsJqAwpMtImkM1M8r1b7/Ryldy/gR/rb Er40G1kRYr7zo7MT+oF3Sn0rNaGuPbMGyJx/hREm/E9tJrH0CHoSmIKEWfx1u+Lu xtyjVTAqGsAEBzng+WFNozeKNr6t9fFmhxXXqnOj79zzjakRbcKCmTtGsDCoc0U5 gZZA8T7IEYiKzncDzSVEQvSvsw/pjTB5apUDj3vn7u/k8lFm57QDg8Bk+3Br7uWK 1KKrscvMWmvTXZqKRx5Dfp85cNIfZ3gt5pPedLW4UCGEktbIsnMKiCSDLVl+q6Pi F4FlPrVCYZmj/3zK8EfAnJxueI4WwNFmNiLyxi1wP7JQNvIFhQoD5gKezF8OfoEc 4U1migkGTZOtlrQvhC0vSjnCIyg00zzJJGruldkXR3GjLxJjIzWdIPBd+OIp5uGa /bKTbrpVGhQ=vVgJ -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://listman.redhat.com/mailman/listinfo/rhsa-announce . 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-5016-1 July 20, 2021 linux, linux-aws, linux-aws-5.8, linux-azure, linux-azure-5.8, linux-gcp, linux-gcp-5.8, linux-hwe-5.8, linux-kvm, linux-oracle, linux-oracle-5.8, linux-raspi vulnerabilities ========================================================================= A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.10 - Ubuntu 20.04 LTS Summary: Several security issues were fixed in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-33909) Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the nfc implementation in the Linux kernel. A privileged local attacker could use this issue to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-23134) It was discovered that a race condition in the kernel Bluetooth subsystem could lead to use-after-free of slab objects. An attacker could use this issue to possibly execute arbitrary code. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-33034) It was discovered that an out-of-bounds (OOB) memory access flaw existed in the f2fs module of the Linux kernel. A local attacker could use this issue to cause a denial of service (system crash). (CVE-2021-3506) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.10: linux-image-5.8.0-1032-raspi 5.8.0-1032.35 linux-image-5.8.0-1032-raspi-nolpae 5.8.0-1032.35 linux-image-5.8.0-1033-kvm 5.8.0-1033.36 linux-image-5.8.0-1037-oracle 5.8.0-1037.38 linux-image-5.8.0-1038-gcp 5.8.0-1038.40 linux-image-5.8.0-1039-azure 5.8.0-1039.42 linux-image-5.8.0-1041-aws 5.8.0-1041.43 linux-image-5.8.0-63-generic 5.8.0-63.71 linux-image-5.8.0-63-generic-64k 5.8.0-63.71 linux-image-5.8.0-63-generic-lpae 5.8.0-63.71 linux-image-5.8.0-63-lowlatency 5.8.0-63.71 linux-image-aws 5.8.0.1041.43 linux-image-azure 5.8.0.1039.40 linux-image-gcp 5.8.0.1038.38 linux-image-generic 5.8.0.63.69 linux-image-generic-64k 5.8.0.63.69 linux-image-generic-lpae 5.8.0.63.69 linux-image-gke 5.8.0.1038.38 linux-image-kvm 5.8.0.1033.36 linux-image-lowlatency 5.8.0.63.69 linux-image-oem-20.04 5.8.0.63.69 linux-image-oracle 5.8.0.1037.36 linux-image-raspi 5.8.0.1032.34 linux-image-raspi-nolpae 5.8.0.1032.34 linux-image-virtual 5.8.0.63.69 Ubuntu 20.04 LTS: linux-image-5.8.0-1037-oracle 5.8.0-1037.38~20.04.1 linux-image-5.8.0-1038-gcp 5.8.0-1038.40~20.04.1 linux-image-5.8.0-1039-azure 5.8.0-1039.42~20.04.1 linux-image-5.8.0-1041-aws 5.8.0-1041.43~20.04.1 linux-image-5.8.0-63-generic 5.8.0-63.71~20.04.1 linux-image-5.8.0-63-generic-64k 5.8.0-63.71~20.04.1 linux-image-5.8.0-63-generic-lpae 5.8.0-63.71~20.04.1 linux-image-5.8.0-63-lowlatency 5.8.0-63.71~20.04.1 linux-image-aws 5.8.0.1041.43~20.04.13 linux-image-azure 5.8.0.1039.42~20.04.11 linux-image-gcp 5.8.0.1038.40~20.04.13 linux-image-generic-64k-hwe-20.04 5.8.0.63.71~20.04.45 linux-image-generic-hwe-20.04 5.8.0.63.71~20.04.45 linux-image-generic-lpae-hwe-20.04 5.8.0.63.71~20.04.45 linux-image-lowlatency-hwe-20.04 5.8.0.63.71~20.04.45 linux-image-oracle 5.8.0.1037.38~20.04.13 linux-image-virtual-hwe-20.04 5.8.0.63.71~20.04.45 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. 7) - noarch, x86_64 3. Description: The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Bug Fix(es): * kernel-rt: update to the latest RHEL7.9.z7 source tree (BZ#1967333) 4. An attacker in a guest VM could use this to write to portions of the host’s physical memory. (CVE-2021-3653) Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host’s physical memory. (CVE-2021-22555) It was discovered that the virtual file system implementation in the Linux kernel contained an unsigned to signed integer conversion error. If you are running a kernel version earlier than the one listed below, please upgrade your kernel as soon as possible

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

local

TYPE

input validation error

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Red Hat

SOURCES

LAST UPDATE DATE

2026-03-23T23:20:49.415000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE