ID

VAR-202107-1361

CVE

CVE-2021-33909

TITLE

Linux Kernel  Classic buffer overflow vulnerability in

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. Linux Kernel Exists in a classic buffer overflow vulnerability. Vendor exploits this vulnerability CID-8cae8cd89f05 It is published as.Information is obtained, information is tampered with, and service operation is interrupted. (DoS) It may be in a state. 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----- . Linux kernel vulnerabilities A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 ESM Summary Several security issues were fixed in the kernel. This affects kernel/bpf/core.c and net/core/filter.c. (CVE-2018-25020) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host’s physical memory. (CVE-2021-3653) Nadav Amit discovered that the hugetlb implementation in the Linux kernel did not perform TLB flushes under certain conditions. A local attacker could use this to leak or alter data from other processes that use huge pages. (CVE-2021-4002) Andy Nguyen discovered that the netfilter subsystem in the Linux kernel contained an out-of-bounds write in its setsockopt() implementation. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-22555) 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) Update instructions The problem can be corrected by updating your kernel livepatch to the following versions: Ubuntu 20.04 LTS aws - 83.1 azure - 83.1 gcp - 83.1 generic - 83.1 gke - 83.1 gkeop - 83.1 lowlatency - 83.1 Ubuntu 18.04 LTS aws - 83.1 generic - 83.1 gke - 83.1 gke - 83.2 gkeop - 83.1 gkeop - 83.2 lowlatency - 83.1 oem - 83.1 Ubuntu 16.04 ESM aws - 83.1 azure - 83.1 generic - 83.1 lowlatency - 83.1 Support Information Kernels older than the levels listed below do not receive livepatch updates. If you are running a kernel version earlier than the one listed below, please upgrade your kernel as soon as possible. Ubuntu 20.04 LTS linux-aws - 5.4.0-1009 linux-azure - 5.4.0-1010 linux-gcp - 5.4.0-1009 linux-gke - 5.4.0-1033 linux-gkeop - 5.4.0-1009 linux-oem - 5.4.0-26 linux - 5.4.0-26 Ubuntu 18.04 LTS linux-aws - 4.15.0-1054 linux-azure-4.15 - 4.15.0-1115 linux-gke-4.15 - 4.15.0-1076 linux-gke-5.4 - 5.4.0-1009 linux-gkeop-5.4 - 5.4.0-1007 linux-hwe-5.4 - 5.4.0-26 linux-oem - 4.15.0-1063 linux - 4.15.0-69 Ubuntu 16.04 ESM linux-aws - 4.4.0-1098 linux-azure - 4.15.0-1063 linux-hwe - 4.15.0-143 linux - 4.4.0-168 Ubuntu 14.04 ESM linux-lts-xenial - 4.4.0-168 References - CVE-2018-25020 - CVE-2021-3653 - CVE-2021-4002 - CVE-2021-22555 - CVE-2021-33909 -- ubuntu-security-announce mailing list ubuntu-security-announce@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-security-announce . 8) - 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 RT source tree to the RHEL-8.4.z2 source tree (BZ#1975405) 4. 7.6) - noarch, x86_64 3. Description: The kernel packages contain the Linux kernel, the core of any Linux operating system. Bug Fix(es): * [CKI kernel builds]: x86 binaries in non-x86 kernel rpms breaks systemtap [7.9.z] (BZ#1975159) 4. Bugs fixed (https://bugzilla.redhat.com/): 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. 8) - 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. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ==================================================================== Red Hat Security Advisory Synopsis: Important: Red Hat Virtualization Host security and bug fix update [ovirt-4.4.7] Advisory ID: RHSA-2021:2736-01 Product: Red Hat Virtualization Advisory URL: https://access.redhat.com/errata/RHSA-2021:2736 Issue date: 2021-07-22 CVE Names: CVE-2021-3447 CVE-2021-33034 CVE-2021-33909 CVE-2021-33910 ==================================================================== 1. Summary: An update for imgbased, redhat-release-virtualization-host, and redhat-virtualization-host is now available for Red Hat Virtualization 4 for Red Hat Enterprise Linux 8. 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: RHEL 8-based RHEV-H for RHEV 4 (build requirements) - noarch, x86_64 Red Hat Virtualization 4 Hypervisor for RHEL 8 - x86_64 3. Description: The redhat-virtualization-host packages provide the Red Hat Virtualization Host. These packages include redhat-release-virtualization-host, ovirt-node, and rhev-hypervisor. Red Hat Virtualization Hosts (RHVH) are installed using a special build of Red Hat Enterprise Linux with only the packages required to host virtual machines. RHVH features a Cockpit user interface for monitoring the host's resources and performing administrative tasks. The redhat-virtualization-host packages provide the Red Hat Virtualization Host. These packages include redhat-release-virtualization-host, ovirt-node, and rhev-hypervisor. Red Hat Virtualization Hosts (RHVH) are installed using a special build of Red Hat Enterprise Linux with only the packages required to host virtual machines. RHVH features a Cockpit user interface for monitoring the host's resources and performing administrative tasks. The ovirt-node-ng packages provide the Red Hat Virtualization Host. These packages include redhat-release-virtualization-host, ovirt-node, and rhev-hypervisor. Red Hat Virtualization Hosts (RHVH) are installed using a special build of Red Hat Enterprise Linux with only the packages required to host virtual machines. RHVH features a Cockpit user interface for monitoring the host's resources and performing administrative tasks. Security Fix(es): * kernel: size_t-to-int conversion vulnerability in the filesystem layer (CVE-2021-33909) * systemd: uncontrolled allocation on the stack in function unit_name_path_escape leads to crash (CVE-2021-33910) * kernel: use-after-free in net/bluetooth/hci_event.c when destroying an hci_chan (CVE-2021-33034) * ansible: multiple modules expose secured values (CVE-2021-3447) 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. Bug Fix(es): * The redhat-release-virtualization-host package no longer requires vdsm-hooks. In this release, the installation of vdsm-hooks is not mandatory for the Red Hat Virtualization Host. (BZ#1976095) * Previously, rhsmcertd was not enabled by default on the Red Hat Virtualization Host. As a result, the systems did not regularly report to RHSM while the subscription-manager reported no obvious issues and repositories were properly enabled. In this release, rhsmcertd is enabled by default in RHVH, and as a result, RHSM now receives reports regularly. (BZ#1958145) * In this release, the Red Hat Virtualization Host has been rebased on top of the RHEL 8.4.0 Batch #1 update. For more information, see the RHEL release notes. (BZ#1957242) * Red Hat Virtualization Host now includes an updated scap-security-guide-rhv which allows you to apply a PCI DSS security profile to the system during installation, (BZ#1883793) 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/2974891 5. Bugs fixed (https://bugzilla.redhat.com/): 1883793 - [RFE] RHV installation with PCI DSS compliance 1939349 - CVE-2021-3447 ansible: multiple modules expose secured values 1955415 - RHVH 4.4: There are AVC denied errors in audit.log after upgrade 1957242 - Rebase RHV-H 4.4.7 on RHEL 8.4.0.1 1958145 - [RHVH 4.4.5] Need to enable rhsmcertd service on the host by default 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 1970887 - CVE-2021-33910 systemd: uncontrolled allocation on the stack in function unit_name_path_escape leads to crash 1970970 - Rebase RHVH 4.4.6 host image with kernel fix for fnic issue 1976005 - No swap on RHVH 4.4.6 1976095 - redhat-release-virtualization-host-content shouldn't have hard dependency on vdsm hooks 1976118 - Failed to enable unit: Unit file rdma.service does not exist in %post execution 1976146 - Include fcoe-utils package into CDN: rhvh-4-for-rhel-8-x86_64-rpms 1976148 - Include vhostmd package into CDN: rhvh-4-for-rhel-8-x86_64-rpms 6. Package List: Red Hat Virtualization 4 Hypervisor for RHEL 8: Source: fcoe-utils-1.0.33-3.git848bcc6.el8.src.rpm redhat-virtualization-host-4.4.7-20210715.1.el8_4.src.rpm vhostmd-1.1-5.el8.src.rpm x86_64: fcoe-utils-1.0.33-3.git848bcc6.el8.x86_64.rpm fcoe-utils-debuginfo-1.0.33-3.git848bcc6.el8.x86_64.rpm fcoe-utils-debugsource-1.0.33-3.git848bcc6.el8.x86_64.rpm redhat-virtualization-host-image-update-4.4.7-20210715.1.el8_4.x86_64.rpm vhostmd-1.1-5.el8.x86_64.rpm vhostmd-debuginfo-1.1-5.el8.x86_64.rpm vhostmd-debugsource-1.1-5.el8.x86_64.rpm vm-dump-metrics-1.1-5.el8.x86_64.rpm vm-dump-metrics-debuginfo-1.1-5.el8.x86_64.rpm vm-dump-metrics-devel-1.1-5.el8.x86_64.rpm RHEL 8-based RHEV-H for RHEV 4 (build requirements): Source: imgbased-1.2.21-1.el8ev.src.rpm redhat-release-virtualization-host-4.4.7-3.el8ev.src.rpm scap-security-guide-0.1.54-2.el8ev.src.rpm noarch: imgbased-1.2.21-1.el8ev.noarch.rpm python3-imgbased-1.2.21-1.el8ev.noarch.rpm redhat-virtualization-host-image-update-placeholder-4.4.7-3.el8ev.noarch.rpm scap-security-guide-rhv-0.1.54-2.el8ev.noarch.rpm x86_64: redhat-release-virtualization-host-4.4.7-3.el8ev.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-2021-3447 https://access.redhat.com/security/cve/CVE-2021-33034 https://access.redhat.com/security/cve/CVE-2021-33909 https://access.redhat.com/security/cve/CVE-2021-33910 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 iQIVAwUBYPmKXdzjgjWX9erEAQjAWRAAjxiveSuwlsiDbILlBSh+W9Lf25i+rrjd oVIdP/JY66MUEe2g5Sq9LXXUudowHbTxC6SAkY8OAn+aTLniwcHrLZSInjmwAgkm NpVwypYx6V2mZoVhAEjdhmFq/u/yH8y2rKnZwaSSUXmKVXPw1+b10mD0s6Gd0ipM 92ETuUmAgEPdhSUcGx2e6lD+lrqR+9E2zz6jNp4kanq2i4/PxnKnP2rpdBmRzMac /IUKj994h028ZCsy4mEgA7f+ckwQ9lGRAOkE5Ck+iOh7DTtt5gTNzdqXkqJm8Pxd 6jmZv9SMdMRs1YJJoqlAwbqFayWWbgmHPLFsSTPS5dKoxycPBgLf9rnaOZ4ep+Pf 1g0tlL894Nkl0zjHGOhpAP0SElPNJfYY84/uoABZp6bLi0Ewa0vKbLchxgXSCSG7 GqlnG1ejaqGiT5zzlUCGQuqprpbbhjq7z7ayhhkMoO8Qo5MXwM8jdOEEBS/BIVg4 z0jI1qScr0c4GZdcDf1lOMsGgCb/HOCsPktGZLaHkh9tTLX+m4kas/HFIsCQVfM8 YymWdaP6S7jvuEh7aq71KX/Uh0o9oduTs9H8STYiKcVsxVgrE5erLP/a2lqAaS7/ ruY3kkn0kAHOSMs5Uytt/JkkmGdBf7PZDCL9rXJtLJ8mPngHlq18c65aVqbeFopM zhC9l8wfg0E=J7Iq -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://listman.redhat.com/mailman/listinfo/rhsa-announce

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

TYPE

overflow

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Red Hat

SOURCES

LAST UPDATE DATE

2026-08-16T22:35:28.252000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE