CVE-2021-3682: debian debian_linux Release of Invalid Pointer or Reference
Vulnerability summary
CVE-2021-3682 is a high (CVSS 8.5) Release of Invalid Pointer or Reference vulnerability in debian debian_linux. EPSS estimates a 2.88% chance of exploitation in the next 30 days, higher than 86.8% of scored vulnerabilities.
Not severe (CVSS 8.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 20 · Related 15Timeline
- 05-08-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.5HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.5HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
- OSV · AlpineEcosystem advisory · calculated8.5HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS trend
Probability
2.88%
Chance of exploitation in the next 30 days
Percentile
87%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.88% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- qemu< 1:6.0+dfsg-3
- debian_linuxEOL9.0 | 10.0 | 11.0
Alpine1 product
- qemu< 6.1.0-r0
Qemu1 product
- qemu< 6.1.0 | 6.1.0:rc1
Redhat1 product
Ubuntu1 product
- qemu< 2.0.0+dfsg-2ubuntu1.47+esm2 | < 1:2.5+dfsg-5ubuntu10.51+esm1 | < 1:2.11+dfsg-1ubuntu7.39 | < 1:4.2-3ubuntu6.21 | < 1:6.2+dfsg-2ubuntu5
5 vendors · 6 products
References
13 links
lists.debian.org/debian-lts-announce/2021/09/msg00000.htmlMailing ListX Refsource MLISTThird Party Advisory- lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing ListX Refsource MLISTThird Party Advisory
