What’s Vulnerable › Vulnerabilities
CVE-2021-44733
- Severity: high (CVSS 7.0 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2021-12-22 · updated 2026-08-05
- Weakness: CWE-362
Description
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.
Affected products
- Debian Linux: 9.0, 10.0, 11.0
- Fedoraproject Fedora: 35
- Linux kernel: from 4.12 before 4.14.261; from 4.15 before 4.19.224; from 4.20 before 5.4.170; from 5.5 before 5.10.89; from 5.11 before 5.15.12 — fixed in 4.14.261, 4.19.224, 5.10.89, 5.15.12, 5.4.170
- NetApp H300E Firmware: all versions
- NetApp H300S Firmware: all versions
- NetApp H410C Firmware: all versions
- NetApp H410S Firmware: all versions
- NetApp H500E Firmware: all versions
- NetApp H500S Firmware: all versions
- NetApp H700E Firmware: all versions
- NetApp H700S Firmware: all versions
- Red Hat Enterprise Linux: 8.0
How to fix
Upgrade to a fixed version: Linux kernel 4.14.261, 4.19.224, 5.10.89, 5.15.12. Check the vendor advisory for mitigations.
References
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
- 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%40linaro.org/
- https://security.netapp.com/advisory/ntap-20220114-0003/
- https://www.debian.org/security/2022/dsa-5096
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
- 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%40linaro.org/
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