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
49%
KEV
Not listed

Published

December 22, 2021

Last Modified

November 21, 2024

References (14)

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.

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 10× in last 7d / 48× 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 113 total refreshes for this CVE.

  1. 2026-07-26 14:52 UTCEPSS rescore
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  3. 2026-07-25 14:15 UTCEPSS rescore
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  6. 2026-07-23 02:05 UTCEG score recompute
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  1. 2026-07-12 05:44 UTCEPSS rescore
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  19. 2026-06-30 01:30 UTCOSV refresh
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  50. 2026-06-12 23:10 UTCEPSS rescore
  51. 2026-06-12 14:10 UTCOSV refresh
  52. 2026-06-11 13:58 UTCEPSS rescore
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  54. 2026-06-10 22:16 UTCEPSS rescore
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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 ↗

Related CVEs(same vendor + same CWE)

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 November 21, 2024. 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 50.8% 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

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