vciy

CVE-2021-3682

INDEX BUILT · 2026-09-20

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A flaw was found in the USB redirector device emulation of QEMU in versions prior to 6.1.0-rc2

CVE-2021-36824 of 4 sources documented this
28

rank 28 = 1 + 21 + 0 + 6 + 0

rank@v1 · scheduled

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.02880  ·  without this subject the record ranks 27

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 8.5, from NVD  ·  without this subject the record ranks 7

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 28

How much of the world it touches

NVD CPE configurations

6 products in the CPE ranges  ·  without this subject the record ranks 22

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 28

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$144,000over the next 30 days, if this record is yours
Movement-$1.25Mon 2022-04-01, the last material move, 4 years, 4 months before this reading
Basisassumeda published average, not your estate

$144,000 = $4.99M incident cost x 1 exposure x 0.0288 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.0288EPSSNOT IN KEVas of 2026-09-20
Severity8.5 HIGHreceipt
Harmtotal lossreceipt
Exploitationnone in held sources
Defenseunaffected versions publishedreceipt
Movementrisenreceipt
PLATEAU10Minimal movement since 2022-04-01, 1585 days at 0.03, as of 2026-08-03. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

Running QEMU? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachnetwork-reachable · low privileges required · no user interaction · high attack complexityreceipt
ImpactComplete confidentiality, integrity and availability loss, with impact beyond the vulnerable componentreceipt
Scored fromCVSS v3.1 · NVD's vectorreceipt
Weakness classCWE-763 Release of Invalid Pointer or Referencereceipt
Published consequencesCWE-763: Integrity, Availability, Confidentiality: Modify Memory, DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

First unaffected version, by branchqemu 6.1.0receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, NVD8.5 HIGHreceipt
Exploit probability0.0288 · top 14% of all CVEsreceipt
Blast breadth3 products across 3 vendorsderived
Assigned byredhatreceipt
Recorded changes47 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productQEMUreceipt
Published rangesqemu < 6.1.0; qemu 6.1.0; redhat enterprise linux 8.0; debian linux 9.0receipt
Show all 6 published ranges
qemu < 6.1.0
qemu 6.1.0
redhat enterprise linux 8.0
debian linux 9.0
debian linux 10.0
debian linux 11.0

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

A flaw was found in the USB redirector device emulation of QEMU in versions prior to 6.1.0-rc2. It occurs when dropping packets during a bulk transfer from a SPICE client due to the packet queue being full. A malicious SPICE client could use this flaw to make QEMU call free() with faked heap chunk metadata, resulting in a crash of QEMU or potential code execution with the privileges of the QEMU process on the host. receipt

NVD's analysis a second authority

severity
8.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
weakness
CWE-763
affected versions
qemu < 6.1.0; qemu 6.1.0; redhat enterprise linux 8.0; and 3 more, listed in full below

check it yourself bugzilla.redhat.com security.netapp.com lists.debian.org debian.org security.gentoo.org lists.debian.org receipt

Dated events

2021-10-05EPSS moved 0.01 to 0.082022-04-01EPSS moved 0.27 to 0.02

Movement the material steps

6 Aug 20210.00731
4 Feb 20220.27305 · crossed 0.10
1 Apr 20220.02199 · crossed 0.10
7 Mar 20230.00125 · scoring model v2023.03.01
17 Mar 20250.0052 · scoring model v2025.03.14
15 Jun 20260.02904 · scoring model v2026.06.15
3 Aug 20260.0288
Show all 47 observations
6 Aug 20210.00731
2 Sep 20210.01095
3 Sep 20210.01458
5 Oct 20210.07673
11 Oct 20210.01819
6 Jan 20220.07673
4 Feb 20220.27305
1 Apr 20220.02199
5 Sep 20220.02422
7 Mar 20230.00125
13 Mar 20230.00130
27 Mar 20230.00162
25 Apr 20230.00165
8 May 20230.00118
8 Jul 20230.00165
28 Oct 20230.00333
1 Feb 20240.00334
17 Dec 20240.00179
17 Mar 20250.0052
22 Mar 20250.00479
29 Mar 20250.02487
30 Mar 20250.00479
15 May 20250.00357
18 May 20250.00492
31 May 20250.00479
4 Jul 20250.0052
21 Sep 20250.00519
1 Oct 20250.00454
3 Oct 20250.00338
6 Oct 20250.00312
8 Oct 20250.0043
21 Oct 20250.00418
27 Oct 20250.00477
28 Oct 20250.00418
18 Nov 20250.02101
21 Nov 20250.00418
24 Nov 20250.00454
2 Dec 20250.00491
27 Dec 20250.00561
28 Dec 20250.00491
26 Feb 20260.00418
21 Mar 20260.0043
28 Mar 20260.00418
1 May 20260.00454
31 May 20260.00477
15 Jun 20260.02904
3 Aug 20260.0288

47 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.0288Published2021-08-05Index as of2026-08-03

The record had been public for 4 years, 11 months when this index was last written.

Published 2021-08-05 receipt · Index as of 2026-08-03 derived

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