CVE-2021-44733: Use After Free
First published: Thu Dec 09 2021(Updated: )
A use-after-free exists in drivers/tee/tee_shm.c in the TEE subsystem in the Linux kernel through 5.15.11. This occurs because of a race condition in tee_shm_get_from_id during an attempt to free a shared memory object.
Credit: cve@mitre.org cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel-rt | <0:4.18.0-372.9.1.rt7.166.el8 | 0:4.18.0-372.9.1.rt7.166.el8 |
| redhat/kernel | <0:4.18.0-372.9.1.el8 | 0:4.18.0-372.9.1.el8 |
| redhat/kernel | <5.16 | 5.16 |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.123-1 6.1.128-1 6.12.12-1 6.12.15-1 | |
| Linux Kernel | <=5.15.11 | |
| Red Hat Enterprise Linux | =8.0 | |
| Fedora | =35 | |
| Debian | =9.0 | |
| Debian | =10.0 | |
| Debian | =11.0 | |
| All of | ||
| netapp h410c firmware | ||
| netapp h410c | ||
| All of | ||
| netapp h300s firmware | ||
| netapp h300s | ||
| All of | ||
| NetApp H500S Firmware | ||
| netapp h500s | ||
| All of | ||
| netapp h700s firmware | ||
| netapp h700s | ||
| All of | ||
| netapp h300e firmware | ||
| netapp h300e | ||
| All of | ||
| netapp h500e firmware | ||
| netapp h500e | ||
| All of | ||
| netapp h700e firmware | ||
| netapp h700e | ||
| All of | ||
| netapp h410s firmware | ||
| netapp h410s | ||
| netapp baseboard management controller h410c firmware | ||
| netapp baseboard management controller h410c | ||
| NetApp Baseboard Management Controller Firmware | ||
| netapp baseboard management controller h300s | ||
| NetApp Baseboard Management Controller Firmware | ||
| netapp baseboard management controller h500s | ||
| NetApp Baseboard Management Controller Firmware | ||
| netapp baseboard management controller h700s | ||
| NetApp Baseboard Management Controller Firmware | ||
| netapp baseboard management controller h300e | ||
| netapp baseboard management controller h500e firmware | ||
| netapp baseboard management controller h500e | ||
| netapp baseboard management controller h700e firmware | ||
| netapp baseboard management controller h700e | ||
| NetApp Baseboard Management Controller Firmware | ||
| netapp baseboard management controller h410s |
Remedy
To mitigate this issue, prevent the modules tee, trusted_tee from being loaded. Please see https://access.redhat.com/solutions/41278 for information on how to blacklist a kernel module to prevent it from loading automatically.
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Reference Links
- https://www.cve.org/CVERecord?id=CVE-2021-44733 https://nvd.nist.gov/vuln/detail/CVE-2021-44733 https://lore.kernel.org/lkml/20211214123540.1789434-1-jens.wiklander@linaro.org/
- https://bugzilla.redhat.com/show_bug.cgi?id=2030747
- https://access.redhat.com/errata/RHSA-2022:1975
- https://access.redhat.com/errata/RHSA-2022:1988
- https://access.redhat.com/security/cve/cve-2021-44733
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/tee/tee_shm.c
- https://github.com/pjlantz/optee-qemu/blob/main/README.md
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://lore.kernel.org/lkml/20211215092501.1861229-1-jens.wiklander@linaro.org/
- https://security.netapp.com/advisory/ntap-20220114-0003/
- https://www.debian.org/security/2022/dsa-5096
- https://lore.kernel.org/lkml/20211214123540.1789434-1-jens.wiklander@linaro.org/
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2033206
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
- https://launchpad.net/bugs/cve/CVE-2021-44733
- https://lore.kernel.org/lkml/20211215092501.1861229-1-jens.wiklander%40linaro.org/
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44733
- https://nvd.nist.gov/vuln/detail/CVE-2021-44733
- https://security-tracker.debian.org/tracker/CVE-2021-44733
- https://ubuntu.com/security/CVE-2021-44733
Frequently Asked Questions
What is the severity of CVE-2021-44733?
CVE-2021-44733 has been rated as having a high severity due to its potential to allow arbitrary code execution in the Linux kernel.
How do I fix CVE-2021-44733?
To fix CVE-2021-44733, upgrade to the kernel versions 0:4.18.0-372.9.1.rt7.166.el8, 0:4.18.0-372.9.1.el8, or any version starting from 5.16.
Which systems are affected by CVE-2021-44733?
CVE-2021-44733 affects various Linux distributions including Red Hat Enterprise Linux 8.0, Fedora 35, and Debian versions 9.0, 10.0, and 11.0.
What is a use-after-free vulnerability related to CVE-2021-44733?
A use-after-free vulnerability occurs when memory is freed but still accessible, allowing malicious exploitation and potential system compromise.
Is there any mitigation for CVE-2021-44733 aside from patching?
There are no specific mitigations for CVE-2021-44733; the recommended action is to apply the provided patches as soon as possible.
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- version/debian/9.0
- version/debian/10.0
- version/debian/11.0
- vendor/netapp
- canonical/netapp h410c firmware
- canonical/netapp h410c
- canonical/netapp h300s firmware
- canonical/netapp h300s
- canonical/netapp h500s firmware
- canonical/netapp h500s
- canonical/netapp h700s firmware
- canonical/netapp h700s
- canonical/netapp h300e firmware
- canonical/netapp h300e
- canonical/netapp h500e firmware
- canonical/netapp h500e
- canonical/netapp h700e firmware
- canonical/netapp h700e
- canonical/netapp h410s firmware
- canonical/netapp h410s
- canonical/netapp baseboard management controller h410c firmware
- canonical/netapp baseboard management controller h410c
- canonical/netapp baseboard management controller firmware
- canonical/netapp baseboard management controller h300s
- canonical/netapp baseboard management controller h500s
- canonical/netapp baseboard management controller h700s
- canonical/netapp baseboard management controller h300e
- canonical/netapp baseboard management controller h500e firmware
- canonical/netapp baseboard management controller h500e
- canonical/netapp baseboard management controller h700e firmware
- canonical/netapp baseboard management controller h700e
- canonical/netapp baseboard management controller h410s