CVE-2021-38578

CRITICALNVD 7.49.8
EchelonGraph scoreMEDIUM confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-03-04. NVD baseline CVSS 7.4; sources differ by 2.4.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 7.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Existing CommBuffer checks in SmmEntryPoint will not catch underflow when computing BufferSize.

CVSS v3
7.4
EG Score
9.8CRITICALmedium confidence
EG Risk
45
EG Risk 45/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.0% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.0%
EPSS %ILE
63rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.0% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

March 3, 2022

Last Modified

November 3, 2025

Advisory Details (2)

Auto-updated Oct 14, 2026
Patch available.
Web page

SA-2023024 - Insyde Software

https://www.insyde.com/security-pledge/SA-2023024
Web pageMentions a patch (unverified)

[SECURITY] [DLA 4207-1] edk2 security update

https://lists.debian.org/debian-lts-announce/2025/06/msg00007.html

Vendor Advisories for CVE-2021-38578(2)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuqemu-efi (0~20160408.ffea0a2c-2ubuntu0.2+esm3) @ xenial2026-10-22ubuntu
redhatedk2-0:20221207gitfff6d81270b5-9.el9_22023-05-09redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
edk22020.11-2, 2020.11-2+deb11u1, 2020.11-2+deb11u2
  • every version up to 2020.11-2+deb11u3: fixed in 2020.11-2+deb11u3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
edk2—
  • every version up to 2022.11-1: fixed in 2022.11-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
edk2—
  • every version up to 2022.11-1: fixed in 2022.11-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
edk2—
  • every version up to 2022.11-1: fixed in 2022.11-1
—

Weakness Classification(2)

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

Additional Vendor Advisories

(1)

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 28× in last 7d / 65× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 95 of 233 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 138 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  2. 2026-10-22 23:45 UTCEG score recompute
  3. 2026-10-22 23:45 UTCVendor advisory
  4. 2026-10-22 23:45 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-22 16:29 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  6. 2026-10-22 01:15 UTCEG score recompute
  7. 2026-10-22 01:15 UTCVendor advisory
  8. 2026-10-22 01:15 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-21 16:28 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  10. 2026-10-21 02:35 UTCEG score recompute
  11. 2026-10-21 02:35 UTCVendor advisory
  12. 2026-10-21 02:35 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-20 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  14. 2026-10-20 03:48 UTCEG score recompute
  15. 2026-10-20 03:48 UTCVendor advisory
  16. 2026-10-20 03:48 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-19 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  18. 2026-10-19 04:34 UTCEG score recompute
  19. 2026-10-19 04:34 UTCVendor advisory
  20. 2026-10-19 04:34 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-18 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  22. 2026-10-18 06:02 UTCEG score recompute
  23. 2026-10-18 06:02 UTCVendor advisory
  24. 2026-10-18 06:02 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-17 16:29 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
Show 70 more
  1. 2026-10-17 07:27 UTCEG score recompute
  2. 2026-10-17 07:27 UTCVendor advisory
  3. 2026-10-17 07:27 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-16 16:33 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  5. 2026-10-16 08:55 UTCEG score recompute
  6. 2026-10-16 08:55 UTCVendor advisory
  7. 2026-10-16 08:54 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-15 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  9. 2026-10-15 08:09 UTCEG score recompute
  10. 2026-10-15 08:09 UTCVendor advisory
  11. 2026-10-15 08:08 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-14 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  13. 2026-10-14 04:18 UTCEG score recompute
  14. 2026-10-14 04:18 UTCVendor advisory
  15. 2026-10-14 04:17 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-13 16:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  17. 2026-10-12 23:57 UTCVendor advisory
  18. 2026-10-12 23:57 UTCGHSA enrichmentGHSA-grqq-3jqg-g95p · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-10-12 19:12 UTCEG score recompute
  20. 2026-10-12 16:29 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  21. 2026-10-11 23:37 UTCEG score recompute
  22. 2026-10-11 13:43 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  23. 2026-10-10 19:56 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-10-09 20:55 UTCOSV refresh
  25. 2026-10-09 20:04 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  26. 2026-10-08 16:39 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  27. 2026-10-07 23:44 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  28. 2026-10-06 15:14 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  29. 2026-10-05 17:40 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  30. 2026-10-04 23:19 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  31. 2026-10-03 14:22 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  32. 2026-10-01 19:46 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  33. 2026-09-30 15:39 UTCEG score recompute
  34. 2026-09-30 15:00 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  35. 2026-09-29 15:15 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  36. 2026-09-28 13:47 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  37. 2026-09-27 13:41 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  38. 2026-09-26 15:54 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  39. 2026-09-26 00:21 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  40. 2026-09-24 14:00 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  41. 2026-09-23 13:44 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  42. 2026-09-22 14:44 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  43. 2026-09-21 20:28 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  44. 2026-09-20 04:35 UTCOSV refresh
  45. 2026-09-19 15:38 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  46. 2026-09-18 19:23 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  47. 2026-09-17 19:23 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  48. 2026-09-16 14:05 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  49. 2026-09-15 03:06 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  50. 2026-09-13 16:43 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  51. 2026-09-12 14:57 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  52. 2026-09-11 14:49 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  53. 2026-09-11 09:33 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  54. 2026-09-08 21:56 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  55. 2026-09-07 15:58 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  56. 2026-09-06 13:45 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  57. 2026-09-05 15:25 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  58. 2026-09-04 13:57 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  59. 2026-09-04 05:03 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  60. 2026-09-02 14:08 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  61. 2026-09-01 13:50 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  62. 2026-09-01 07:53 UTCOSV refresh
  63. 2026-09-01 03:32 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  64. 2026-08-30 19:14 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  65. 2026-08-30 01:19 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  66. 2026-08-28 21:37 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  67. 2026-08-27 14:22 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  68. 2026-08-26 14:42 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  69. 2026-08-25 13:46 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  70. 2026-08-24 14:13 UTCEPSS rescoreEPSS 1.0% · 60th percentile

Frequently asked(5)

What is CVE-2021-38578?
CVE-2021-38578 is a critical-severity vulnerability; its CVE record was published on March 3, 2022. Existing CommBuffer checks in SmmEntryPoint will not catch underflow when computing BufferSize.
When was the CVE record for CVE-2021-38578 published?
The CVE record for CVE-2021-38578 was published on March 3, 2022. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 3, 2025; the record at its source may have been updated since.
Is CVE-2021-38578 actively exploited?
CVE-2021-38578 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (63rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-38578?
CVE-2021-38578 has a CVSS v3 base score of 7.4 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.8 (CRITICAL).
How do I remediate CVE-2021-38578?
A fix for CVE-2021-38578 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-38578 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-38578

Explore →

Is Your Infrastructure Affected by CVE-2021-38578?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.