The Network Block Device (NBD) server in Quick Emulator (QEMU) before 2.11 is vulnerable to a denial of service issue.
The Network Block Device (NBD) server in Quick Emulator (QEMU) before 2.11 is vulnerable to a denial of service issue. It could occur if a client sent large option requests, making the server waste CPU time on reading up to 4GB per request. A client could use this flaw to keep the NBD server from serving other requests, resulting in DoS.
- Published
- Jul 27, 2018
- Updated
- Jun 16, 2026
- EPSS
- 3.3% · 88th percentile
- CWE
- CWE-400
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Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.3%
CNA vs NVD score
- NVD
- 8.6
- CNA · redhat
- 5.8
- 2.8 point gap
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| qemu | qemu | cpe:2.3:a:qemu:qemu |
| redhat | virtualization | cpe:2.3:a:redhat:virtualization |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux17.10
- debian debian linux9.0
- qemu qemubefore 2.11.0
- redhat virtualization4.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
QEMU qemu
- 2.11affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | qemu | before 1:2.11+dfsg-1 | 1:2.11+dfsg-1 |
| Debian:9 | qemu | before 1:2.8+dfsg-6+deb9u4 | 1:2.8+dfsg-6+deb9u4 |
| Red Hat:enterprise_linux:7::hypervisor | qemu-img-rhev | before 10:2.10.0-21.el7 | 10:2.10.0-21.el7 |
| Red Hat:enterprise_linux:7::hypervisor | qemu-kvm-common-rhev | before 10:2.10.0-21.el7 | 10:2.10.0-21.el7 |
| Red Hat:enterprise_linux:7::hypervisor | qemu-kvm-rhev | before 10:2.10.0-21.el7 | 10:2.10.0-21.el7 |
| Red Hat:enterprise_linux:7::hypervisor | qemu-kvm-rhev-debuginfo | before 10:2.10.0-21.el7 | 10:2.10.0-21.el7 |
| Red Hat:enterprise_linux:7::hypervisor | qemu-kvm-tools-rhev | before 10:2.10.0-21.el7 | 10:2.10.0-21.el7 |
| SUSE:Linux Enterprise Desktop 12 SP2 | qemu | before 2.6.2-41.37.1 | 2.6.2-41.37.1 |
| SUSE:Linux Enterprise Desktop 12 SP3 | qemu | before 2.9.1-6.12.1 | 2.9.1-6.12.1 |
Same product
qemu: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-12928The QMP migrate command in QEMU version 4.0.0 and earlier is vulnerable to OS command injection, which allows the remote attacker to achieve46Plan
- CVE-2015-8556Local privilege escalation vulnerability in the Gentoo QEMU package before 2.5.0-r1.44Plan
- CVE-2017-15118A stack-based buffer overflow vulnerability was found in NBD server implementation in qemu before 2.11 allowing a client to request an expor43Plan
- CVE-2022-36648The hardware emulation in the of_dpa_cmd_add_l2_flood of rocker device model in QEMU, as used in 7.0.0 and earlier, allows remote attackers 41Plan
- CVE-2017-16845hw/input/ps2.c in Qemu does not validate 'rptr' and 'count' values during guest migration, leading to out-of-bounds access.41Plan
- CVE-2016-7161Heap-based buffer overflow in the .receive callback of xlnx.xps-ethernetlite in QEMU (aka Quick Emulator) allows attackers to execute arbitr41Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:qemu | 1:2.11+dfsg-1 · Debian:12 | Package registry (OSV) |
| red hat:qemu-img-rhev | 10:2.10.0-21.el7 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:qemu-kvm-common-rhev | 10:2.10.0-21.el7 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:qemu-kvm-rhev | 10:2.10.0-21.el7 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:qemu-kvm-rhev-debuginfo | 10:2.10.0-21.el7 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:qemu-kvm-tools-rhev | 10:2.10.0-21.el7 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| suse:qemu | 2.9.1-6.12.1 · SUSE:Linux Enterprise Desktop 12 SP3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-400 · Uncontrolled Resource ConsumptionCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
nvd-primary
Root cause
Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.
The bug in code
The whole CWE-400 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
function expand(node) { return node.children.map(expand);}Fixed
const MAX_DEPTH = 32;function expand(node, depth = 0) { if (depth > MAX_DEPTH) throw new Error("too deep"); return node.children.map((c) => expand(c, depth + 1));}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2017/11/28/9
- www.securityfocus.com/bid/102011
- access.redhat.com/errata/RHSA-2018:1104
- access.redhat.com/errata/RHSA-2018:1113
- bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-15119
- lists.gnu.org/archive/html/qemu-devel/2017-11/msg05044.html
- usn.ubuntu.com/3575-1/
- www.debian.org/security/2018/dsa-4213
Vendor advisories and official records. Exploit/PoC links are deliberately left out.