CVE-2021-3527: debian debian_linux
Vulnerability summary
CVE-2021-3527 is a medium (CVSS 5.5) vulnerability in debian debian_linux. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 31.4% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 16 · Related 15Timeline
- 26-05-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
A flaw was found in the USB redirector device (usb-redir) of QEMU. Small USB packets are combined into a single, large transfer request, to reduce the overhead and improve performance. The combined size of the bulk transfer is used to dynamically allocate a variable length array (VLA) on the stack without proper validation. Since the total size is not bounded, a malicious guest could use this flaw to influence the array length and cause the QEMU process to perform an excessive allocation on the stack, resulting in a denial of service.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · AlpineEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.37%
Chance of exploitation in the next 30 days
Percentile
31%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.37% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- qemu< 1:5.2+dfsg-11
- debian_linuxEOL9.0 | 10.0
Alpine1 product
- qemu< 6.0.0-r2
Qemu1 product
- qemu≤ 6.0.0
Redhat1 product
Ubuntu1 product
- qemu< 2.0.0+dfsg-2ubuntu1.47+esm6 | < 1:2.5+dfsg-5ubuntu10.51+esm4 | < 1:2.11+dfsg-1ubuntu7.37 | < 1:4.2-3ubuntu6.17 | < 1:6.0+dfsg-2expubuntu1
5 vendors · 6 products
References
18 links- www.openwall.com/lists/oss-security/2021/05/05/5X Refsource MISCMailing ListPatchThird Party Advisory
- gitlab.com/qemu-project/qemu/-/commit/7ec54f9eb62b5d177e30eb8b1cad795a5f8d8986X Refsource MISCPatchThird Party Advisory
- gitlab.com/qemu-project/qemu/-/commit/05a40b172e4d691371534828078be47e7fff524cX Refsource MISCPatchThird Party Advisory
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
