CVE-2021-3700
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the...
CVE-2021-3700 is a medium vulnerability (CVSS 6.4) in Microsoft Usbredir, published September 30, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 24th percentile. Fixed in usbredir 0.12.0-r0.
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 4.4 Medium
AV:L/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-416
- Updated
- 2026-11-02
CVE List No score
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
CVE-2021-3700- Weakness
- CWE-416
- Updated
- 2026-11-02
EUVDEUVD-2021-26985 No score
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
EUVD-2021-26985- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-9885-wxqj-48q7
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the...
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
GHSA-9885-wxqj-48q7- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVALPINE-CVE-2021-3700
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
ALPINE-CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
OSVAZL-8824
6.4
CVE-2021-3700 affecting package usbredir for versions less than 0.12.0-1
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
AZL-8824- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 8 moreShow less
OSVBELL-CVE-2021-3700
6.4
CVE-2021-3700 does not affect BellSoft software
- Record
BELL-CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSV
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-3700
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
DEBIAN-CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVOESA-2021-1355
3.9
usbredir security update
usbredir is the name of a network protocol for sending USB device traffic over a network connection. It is also the name of the software package offering a parsing library, a usbredirhost library and several utilities implementing this protocol. It also including a USB host TCP server, using libusbredirhost.
Security Fix(es):
No description is available for this CVE.(CVE-2021-3700)
- Record
OESA-2021-1355- CVSS 3.1
- 3.9 Low
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-3700
6.4
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination.
- Record
UBUNTU-CVE-2021-3700- CVSS 3.1
- 6.4 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVMGASA-2022-0133 No score
Updated usbredir packages fix security vulnerability
A use-after-free vulnerability was found in usbredir in versions prior to 0.11.0 in the usbredirparser_serialize() in usbredirparser/usbredirparser.c. This issue occurs when serializing large amounts of buffered write data in the case of a slow or blocked destination. (CVE-2021-3700)
- Record
MGASA-2022-0133- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11489-1 No score
libusbredirhost1-0.11.0-1.2 on GA media
These are all security issues fixed in the libusbredirhost1-0.11.0-1.2 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11489-1- Updated
- 2026-11-02
OSVUSN-5784-1 No score
usbredir vulnerability
It was discovered that usbredir incorrectly handled memory when serializing large amounts of data in the case of a slow or blocked destination. An attacker could possibly use this issue to cause applications using usbredir to crash, resulting in a denial of service, or possibly execute arbitrary code.
- Record
USN-5784-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
usbredirAlpine:v3.16 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.17 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.18 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.19 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.20 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.21 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.22 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.23 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAlpine:v3.24 |
before 0.12.0-r0 | 0.12.0-r0 |
usbredirAzure Linux:2 |
before 0.12.0-1 | 0.12.0-1 |
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| Package | Affected | Fixed |
|---|---|---|
usbredirDebian:12 |
before 0.11.0-1 | 0.11.0-1 |
usbredirDebian:13 |
before 0.11.0-1 | 0.11.0-1 |
usbredirDebian:14 |
before 0.11.0-1 | 0.11.0-1 |
usbredirDebian:9 |
before 0.7.1-1+deb9u1, plus listed versions 0.7.1-1 |
0.7.1-1+deb9u1 |
usbredirMageia:8 |
before 0.8.0-3.1.mga8 | 0.8.0-3.1.mga8 |
usbrediropenEuler:20.03-LTS-SP1 |
before 0.8.0-5.oe1 | 0.8.0-5.oe1 |
usbrediropenEuler:20.03-LTS-SP2 |
before 0.8.0-5.oe1 | 0.8.0-5.oe1 |
usbredirUbuntu:Pro:14.04:LTS |
before 0.6-2ubuntu1.1+esm1, plus listed versions 0.6-20.6-2ubuntu10.6-2ubuntu1.1 |
0.6-2ubuntu1.1+esm1 |
usbredirUbuntu:Pro:16.04:LTS |
before 0.7.1-1ubuntu0.16.04.1~esm1, plus listed versions 0.7-1ubuntu20.7.1-1 |
0.7.1-1ubuntu0.16.04.1~esm1 |
usbredirUbuntu:18.04:LTS |
before 0.7.1-1ubuntu0.18.04.1, plus listed versions 0.7.1-1 |
0.7.1-1ubuntu0.18.04.1 |
usbredirUbuntu:20.04:LTS |
before 0.8.0-1ubuntu0.1, plus listed versions 0.8.0-1 |
0.8.0-1ubuntu0.1 |
usbrediropenSUSE:Tumbleweed |
before 0.11.0-1.2 | 0.11.0-1.2 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | affected, aliases, references | OSV |
| 2026-11-03 | aliases, products | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
bugzilla.redhat.com/show_bug.cgi?id=1992830
gitlab.freedesktop.org/spice/usbredir/-/commit/03c519ff5831ba
lists.debian.org/debian-lts-announce/2022/03/msg00030.html
nvd.nist.gov/vuln/detail/CVE-2021-3700
github.com/advisories/GHSA-9885-wxqj-48q7
security.alpinelinux.org/vuln/CVE-2021-3700
Show 11 moreShow less
docs.bell-sw.com/security/cves/CVE-2021-3700
security-tracker.debian.org/tracker/CVE-2021-3700
advisories.mageia.org/MGASA-2022-0133.html
bugs.mageia.org/show_bug.cgi?id=30194
debian.org/lts/security/2022/dla-2958
openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2021-1355
ubuntu.com/security/CVE-2021-3700
access.redhat.com/security/cve/CVE-2021-3700
ubuntu.com/security/notices/USN-5784-1
cve.org/CVERecord?id=CVE-2021-3700
suse.com/security/cve/CVE-2021-3700