A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0.
A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 help- Published
- May 13, 2021
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 24th percentile
- CWE
- CWE-367
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Affected systems
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux9.0
- qemu qemuup to 5.2.0 inclusive
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.
n/a qemu
- up to, including 5.2.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | qemu | before 1:3.1+dfsg-8+deb10u9 | 1:3.1+dfsg-8+deb10u9 |
| Debian:12 | qemu | before 1:5.2+dfsg-4 | 1:5.2+dfsg-4 |
| Debian:9 | qemu | before 1:2.8+dfsg-6+deb9u13 | 1:2.8+dfsg-6+deb9u13 |
| openSUSE:Leap 15.2 | qemu | before 4.2.1-lp152.9.9.2 | 4.2.1-lp152.9.9.2 |
| openSUSE:Leap 15.2 | qemu-linux-user | before 4.2.1-lp152.9.9.3 | 4.2.1-lp152.9.9.3 |
| openSUSE:Leap 15.2 | qemu-testsuite | before 4.2.1-lp152.9.9.5 | 4.2.1-lp152.9.9.5 |
| SUSE:HPE Helion OpenStack 8 | qemu | before 2.9.1-6.47.1 | 2.9.1-6.47.1 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | qemu | before 2.11.2-9.43.1 | 2.11.2-9.43.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP2 | qemu | before 4.2.1-11.13.1 | 4.2.1-11.13.1 |
| SUSE:Linux Enterprise Point of Sale 11 SP3 | kvm | before 1.4.2-53.38.1 | 1.4.2-53.38.1 |
| SUSE:Linux Enterprise Server 11 SP4-LTSS | kvm | before 1.4.2-60.34.1 | 1.4.2-60.34.1 |
| SUSE:Linux Enterprise Server 12 SP2-BCL | qemu | before 2.6.2-41.62.1 | 2.6.2-41.62.1 |
| SUSE:Linux Enterprise Server 12 SP5 | qemu | before 3.1.1.1-48.2 | 3.1.1.1-48.2 |
| SUSE:OpenStack Cloud 9 | qemu | before 2.11.2-5.29.1 | 2.11.2-5.29.1 |
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 | 1:5.2+dfsg-4 · Debian:12 | Package registry (OSV) |
| opensuse:qemu | 4.2.1-lp152.9.9.2 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:qemu-linux-user | 4.2.1-lp152.9.9.3 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:qemu-testsuite | 4.2.1-lp152.9.9.5 · openSUSE:Leap 15.2 | Package registry (OSV) |
| suse:kvm | 1.4.2-60.34.1 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:qemu | 4.2.1-11.13.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP2 | 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
- Someone with local access to the system can trigger it.
- Administrator privileges are required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-367 · Time-of-check Time-of-use (TOCTOU) Race ConditionCVSS vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.redhat.com/show_bug.cgi?id=1927007
- lists.debian.org/debian-lts-announce/2021/02/msg00024.html
- lists.debian.org/debian-lts-announce/2022/09/msg00008.html
- security.netapp.com/advisory/ntap-20210720-0009/
- www.zerodayinitiative.com/advisories/ZDI-21-159/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.