CVE-2021-44733

HIGHNVD 7.07.0—
EchelonGraph scoreMEDIUM confidence

Score 7.0 from GitHub Security Advisory (severity: HIGH) published 2021-12-23. NVD baseline CVSS 7.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.0Exploit: Elevated riskExposed: 0

A fix is available — apply it.

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.

CVSS v3
7.0
EG Score
7.0(medium)
EG Risk
52(Track)
EG Risk 52/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity70% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
51%
KEV
Not listed

Published

December 22, 2021

Last Modified

August 5, 2026

Advisory Details (7)

Auto-updated Aug 5, 2026
🔬 Proof of concept available. Patch available.
generic🟡 PoC Available

optee-qemu/README.md at main · pjlantz/optee-qemu · GitHub

https://github.com/pjlantz/optee-qemu/blob/main/README.md
generic

kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/tee/tee_shm.c
generic

tee: handle lookup of shm with reference count 0 - kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
generic Patch Available

[SECURITY] [DSA 5096-1] linux security update

https://www.debian.org/security/2022/dsa-5096
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20220114-0003/
generic

[PATCH v2] tee: handle lookup of shm with reference count 0 - Jens Wiklander

https://lore.kernel.org/lkml/20211215092501.1861229-1-jens.wiklander%40linaro.org/
generic Patch Available

[SECURITY] [DLA 2941-1] linux-4.19 security update

https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html

Vendor Advisories for CVE-2021-44733(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-buildinfo-5.14.0-1022-oem (5.14.0-1022.24) @ focal2026-05-26ubuntu
ubuntulinux-image-unsigned-5.13.0-37-lowlatency (5.13.0-37.42) @ impish2026-05-26ubuntu
ubuntulinux-headers-azure-fde (5.4.0.1073.76+cvm1.19) @ focal2026-05-26ubuntu
ubuntulinux-signed-image-lowlatency-hwe-16.04-edge (4.15.0.173.162) @ bionic2026-05-26ubuntu
ubuntulinux-tools-5.13.0-1021-azure (5.13.0-1021.24~20.04.1) @ focal2026-05-26ubuntu
ubuntulinux-headers-bluefield (5.4.0.1032.33) @ focal2026-05-26ubuntu
redhatkernel-rt-0:4.18.0-372.9.1.rt7.166.el82022-05-10redhat
redhatkernel-0:4.18.0-372.9.1.el82022-05-10redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(6 across 6 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
linux4.19.118-1 ... 4.19.98-1~bpo9+1 (36 versions)4.19.232-1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux5.10.46-4 ... 5.10.92-1~bpo10+1 (6 versions)5.10.92-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.15-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.15-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.15-1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
linux-4.194.19.132-1~deb9u1 ... 4.19.208-1~deb9u1 (10 versions)4.19.232-1~deb9u1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(7)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 160 total refreshes for this CVE.

  1. 2026-09-07 17:51 UTCOSV refresh
  2. 2026-09-07 15:58 UTCEPSS rescore
  3. 2026-09-06 13:45 UTCEPSS rescore
  4. 2026-09-05 15:25 UTCEPSS rescore
  5. 2026-09-04 13:57 UTCEPSS rescore
  6. 2026-09-04 05:03 UTCEPSS rescore
  7. 2026-09-02 14:09 UTCEPSS rescore
  8. 2026-09-01 13:50 UTCEPSS rescore
  9. 2026-09-01 03:33 UTCEPSS rescore
  10. 2026-08-30 19:14 UTCEPSS rescore
  11. 2026-08-30 19:14 UTCEPSS rescore
  12. 2026-08-30 01:19 UTCEPSS rescore
  13. 2026-08-28 21:37 UTCEPSS rescore
  14. 2026-08-27 14:22 UTCEPSS rescore
  15. 2026-08-26 14:43 UTCEPSS rescore
  16. 2026-08-25 13:46 UTCEPSS rescore
  17. 2026-08-24 14:13 UTCEPSS rescore
  18. 2026-08-23 00:16 UTCEPSS rescore
  19. 2026-08-21 23:46 UTCEPSS rescore
  20. 2026-08-21 03:23 UTCOSV refresh
  21. 2026-08-20 22:52 UTCEPSS rescore
  22. 2026-08-20 22:52 UTCEPSS rescore
  23. 2026-08-19 17:01 UTCEPSS rescore
  24. 2026-08-18 13:45 UTCEPSS rescore
  25. 2026-08-17 13:44 UTCEPSS rescore
Show 75 more
  1. 2026-08-16 14:53 UTCEPSS rescore
  2. 2026-08-16 02:11 UTCEPSS rescore
  3. 2026-08-15 01:27 UTCEPSS rescore
  4. 2026-08-13 21:57 UTCEPSS rescore
  5. 2026-08-12 13:48 UTCEPSS rescore
  6. 2026-08-11 13:38 UTCEPSS rescore
  7. 2026-08-09 13:44 UTCEPSS rescore
  8. 2026-08-08 16:33 UTCEPSS rescore
  9. 2026-08-07 16:24 UTCEPSS rescore
  10. 2026-08-06 13:44 UTCEPSS rescore
  11. 2026-08-05 19:14 UTCEPSS rescore
  12. 2026-08-05 18:32 UTCEG score recompute
  13. 2026-08-05 18:32 UTCVendor advisory
  14. 2026-08-05 18:32 UTCGHSA enrichment
  15. 2026-08-04 10:34 UTCEPSS rescore
  16. 2026-08-04 07:57 UTCOSV refresh
  17. 2026-08-03 10:33 UTCEPSS rescore
  18. 2026-08-02 02:24 UTCEPSS rescore
  19. 2026-08-01 04:13 UTCEPSS rescore
  20. 2026-07-30 16:25 UTCEPSS rescore
  21. 2026-07-30 01:28 UTCEPSS rescore
  22. 2026-07-28 15:33 UTCEPSS rescore
  23. 2026-07-26 14:52 UTCEPSS rescore
  24. 2026-07-26 14:52 UTCEPSS rescore
  25. 2026-07-25 14:15 UTCEPSS rescore
  26. 2026-07-24 14:15 UTCEPSS rescore
  27. 2026-07-23 14:16 UTCEPSS rescore
  28. 2026-07-23 02:05 UTCEG score recompute
  29. 2026-07-22 22:52 UTCEG score recompute
  30. 2026-07-22 14:06 UTCEPSS rescore
  31. 2026-07-21 15:22 UTCEPSS rescore
  32. 2026-07-21 15:22 UTCEPSS rescore
  33. 2026-07-20 17:05 UTCEPSS rescore
  34. 2026-07-19 14:29 UTCEPSS rescore
  35. 2026-07-19 02:27 UTCEPSS rescore
  36. 2026-07-18 10:02 UTCEPSS rescore
  37. 2026-07-18 10:02 UTCEPSS rescore
  38. 2026-07-18 05:29 UTCOSV refresh
  39. 2026-07-16 17:00 UTCEPSS rescore
  40. 2026-07-16 17:00 UTCEPSS rescore
  41. 2026-07-15 16:55 UTCEPSS rescore
  42. 2026-07-15 16:55 UTCEPSS rescore
  43. 2026-07-15 01:58 UTCEPSS rescore
  44. 2026-07-13 22:27 UTCEPSS rescore
  45. 2026-07-13 22:27 UTCEPSS rescore
  46. 2026-07-13 06:11 UTCEPSS rescore
  47. 2026-07-13 06:11 UTCEPSS rescore
  48. 2026-07-12 05:44 UTCEPSS rescore
  49. 2026-07-11 08:25 UTCEPSS rescore
  50. 2026-07-11 08:25 UTCEPSS rescore
  51. 2026-07-09 19:07 UTCEPSS rescore
  52. 2026-07-08 15:12 UTCEPSS rescore
  53. 2026-07-07 13:43 UTCEPSS rescore
  54. 2026-07-06 16:25 UTCEPSS rescore
  55. 2026-07-06 16:25 UTCEPSS rescore
  56. 2026-07-06 02:21 UTCEPSS rescore
  57. 2026-07-06 02:21 UTCEPSS rescore
  58. 2026-07-05 02:28 UTCEPSS rescore
  59. 2026-07-05 02:28 UTCEPSS rescore
  60. 2026-07-04 06:29 UTCEPSS rescore
  61. 2026-07-04 06:29 UTCEPSS rescore
  62. 2026-07-02 16:57 UTCEPSS rescore
  63. 2026-07-01 15:04 UTCEPSS rescore
  64. 2026-06-30 23:20 UTCEPSS rescore
  65. 2026-06-30 23:20 UTCEPSS rescore
  66. 2026-06-30 01:30 UTCOSV refresh
  67. 2026-06-29 14:04 UTCEPSS rescore
  68. 2026-06-28 14:05 UTCEPSS rescore
  69. 2026-06-28 04:54 UTCEPSS rescore
  70. 2026-06-28 04:54 UTCEPSS rescore
  71. 2026-06-27 03:06 UTCEPSS rescore
  72. 2026-06-27 03:06 UTCEPSS rescore
  73. 2026-06-25 13:48 UTCEPSS rescore
  74. 2026-06-25 13:48 UTCEPSS rescore
  75. 2026-06-24 14:03 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCpjlantz/optee-qemu
    First seen Dec 23, 2021

    Environment with vulnerable kernel for exploitation of the TEE driver (CVE-2021-44733)

    Open source ↗

Frequently asked(5)

What is CVE-2021-44733?
CVE-2021-44733 is a high vulnerability published on December 22, 2021. A use-after-free exists in drivers/tee/teeshm.c in the TEE subsystem in the Linux kernel through 5.15.11. This occurs because of a race condition in teeshmgetfrom_id during an attempt to free a shared memory object.
When was CVE-2021-44733 disclosed?
CVE-2021-44733 was first published in the National Vulnerability Database on December 22, 2021, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-44733 actively exploited?
CVE-2021-44733 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 49.1% of all scored CVEs.
What is the CVSS score of CVE-2021-44733?
CVE-2021-44733 has a CVSS v3 base score of 7.0 (NVD).
How do I remediate CVE-2021-44733?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-44733, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-44733

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