HOMEVULNERABILITIESCVE-2021-20255
MEDIUM

CVE-2021-20255

CWE-835Published: March 9, 2021· Updated: Jun 17, 2026

5.5
CVSS v3.1

Official Description

A stack overflow via an infinite recursion vulnerability was found in the eepro100 i8255x device emulator of QEMU. This issue occurs while processing controller commands due to a DMA reentry issue. This flaw allows a guest user or process to consume CPU cycles or crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

NVD Source

Technical Analysis

CVE-2021-20255 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
qemu1 product(s)
qemu
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1930646
PATCHhttps://www.openwall.com/lists/oss-security/2021/02/25/1
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1930646
PATCHhttps://www.openwall.com/lists/oss-security/2021/02/25/1
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/04/msg00009.html
ADVISORYhttps://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1
ADVISORYhttps://security.netapp.com/advisory/ntap-20210507-0003/
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/04/msg00009.html
ADVISORYhttps://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1
ADVISORYhttps://security.netapp.com/advisory/ntap-20210507-0003/

All References (10)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1930646Issue Tracking · Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.htmlMailing List · Third Party Advisory
→
https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210507-0003/Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2021/02/25/1Mailing List · Patch · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1930646Issue Tracking · Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.htmlMailing List · Third Party Advisory
→
https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210507-0003/Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2021/02/25/1Mailing List · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-20255
CVSS Score5.5 / 10
SeverityMEDIUM
WeaknessCWE-835
CISA KEVNo
Affected2 vendor(s)
PublishedMar 9, 2021

Related CVEs (CWE-835)

CVE-2018-20784
9.8
CVE-2017-12997
9.8
CVE-2017-12990
9.8
CVE-2017-12995
9.8
CVE-2021-42143
9.1
CVE-2024-43366
9.1

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-20255 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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